Listing by next-address also returned the reserved-multicast entries STP
writes, shown as port 1 with a delete button, while l2_delete() still
looks up by next-unicast and so removed the unicast entry after that
index instead. The change was there to show the LACP steering entries;
delivery by trap writes none, so it goes.
Both paths wrote the trunk registers directly and left the protocol
running on the group, so "lag show" said disabled while the partner kept
both links in one aggregate, and re-sending the LACP line did not repair
it because the same-ports shortcut returns early. Each path now releases
the group from LACP first; for a group that never ran LACP that is a
no-op.
The receive machine armed current_while from the partner's TIMEOUT bit,
so against a partner on the slow rate a port whose LACPDUs stopped with
the link still up stayed in the trunk for the long timeout, two minutes.
802.3ad 43.4.12 starts the timer from the actor's own LACP_Timeout, and
we always advertise the short one: the partner sends every second and is
let go after the short timeout.
Sandbox T23 plays a slow-rate partner that goes quiet and fails on the
code before this.
Dynamic link aggregation on top of the static LAGG, for RTL8372/8373:
receive, selection and mux state machines (coupled mux, one aggregator
per group), with "lacp show" to look inside. Each of the four trunk
groups runs its own aggregator on the candidate ports assigned with
"lag <n> lacp <ports>"; the engine starts with the first such group and
stops with the last.
LACPDUs reach the CPU through the reserved-multicast trap, so delivery
needs no L2 entry and nothing written per VLAN or per PVID. The trap
acts on the address before the VLAN lookup and before the ingress
filters, so a LACPDU also arrives on a port that admits tagged frames
only and on a port STP holds in blocking, neither of which a forwarded
one reaches. A trapped frame carries no VLAN tag,
so lacp_in() takes the offset of the PDU body from TRAP_RX_BODY(). The
action is set with trap_rma_set(), which leaves the flags sharing that
register alone, and "lacp off" puts the slow-protocols drop default
back. doc/lacp.md and doc/link_aggregation.md record what was measured,
including why the trap looked like a dead end at first.
The web UI gets a Static/LACP mode per group on the LAG page with live
status, and the startup-config validator knows the per-group syntax. A
host-side sandbox for the state machines runs in the test harness
together with the LAG hash check. It drives both forms of an incoming
LACPDU, so the body offset of a trapped one is covered as well.
The L2 table page iterated with the "next unicast" read method, so
static multicast entries such as an IGMP group were invisible. It now
iterates with "next address", skips L3 entries (their layout carries IP
addresses where a MAC is expected), and reports the lowest member of a
multicast entry's port mask, so such an entry shows up as a static
entry on that port.
A port taken out of LACP forgets its partner, so "lacp show" after
"lacp off" no longer reports one. Applying the same candidate set to a
group again, as the LAG page does on every Apply, leaves the trunk
alone instead of tearing it down for a second or two. lacp_in() checks
the frame length and ethertype before reading a LACPDU, so a runt or a
foreign frame on the slow-protocols address cannot leave stale buffer
bytes as a partner. The sandbox covers these three in T20-T22. On the
LAG page, LACP mode with no ports checked sends "lag N lacp off", and
the startup-config validator wants at least one port after "lacp".
A reserved-multicast trap goes to the port named in EXT_CPU_CTRL, which
names no port out of reset, so trapped frames were dropped at ingress.
trap_init() points it at the CPU port once at startup, and
trap_rma_set() changes only the action field of an RMA register.
A trapped frame arrives without the VLAN tag a forwarded one gets, so
TRAP_RX_BODY() gives the offset of the payload for both forms.
STP now traps its address while it runs instead of steering it with a
static L2 entry per VLAN, so turning it on no longer walks the VLAN
table and a pvid change no longer needs stp off and on. With STP off
the flooding entries are restored as before.
A trapped BPDU passes the tagged-only ingress filter that drops a
forwarded one, so the stp_setup() warning about such ports goes.
Opcode 0x48 outputs 8 dummy clocks between the address and the first data
byte. flash_configure_sio() sets DUMMYCYCLES to 0 and flash_read_security()
never raises it, so the controller captures the dummy slot as the first of
its four data bytes while the address still advances by four. The printed
output therefore shows 0xff in place of every fourth byte and skips one
content byte per transfer. flash_read_uid() already sets DUMMYCYCLES for
opcode 0x4b, which needs the same allowance.
The answer to a lookup arrives after the command has returned, so the
console of the web interface never shows it. Plain "dns" now prints the
name and the address, or whether it is still pending or failed.
leds_dump() printed the pin mux, the LED enables and every LED set on each
boot, from BANK2. It now lives in its own file in BANK3, where there is
room, and runs only on the new "leds" command, next to gpio and sds, so it
stays at hand for bringing up a new board without costing BANK2 or boot
output.
A matrix of the ports, one row per ingress port, showing which ports a
frame entering there may leave through. The port number of a row turns
red when the port is not fully open, and the cell for the port itself is
marked since it is always allowed. Apply sends one "isolate" command per
changed row, and Allow all ticks the whole matrix.
The switch side is a new /isolation.json, which reports each port's
allowance mask read back from the hardware. The page is an Isolation
section of the single-page UI.
494320b removed strcpy() from rtl837x_flash.c but left its declaration
in rtl837x_common.h. Since then the linker has taken strcpy from the
SDCC library instead, which expects the destination as a generic pointer
in DPL, DPH and B. The callers pass an __xdata pointer and leave B as it
is, so the copy lands wherever B happens to point. boot.c only gets away
with it because B is zero there; a call with B set, as from the ChaCha20
test in #207, writes into internal RAM and stops the 8051.
Only frames to 01:00:5e:00:00:16 reached the IGMP handler, so v1/v2
reports, which go to the group address, were never seen. The handler
also took the group from the first v3 group record for every type.
Pass all IPv4 multicast to the handler, which takes the IGMP header
from the IP header length, the group from the IGMP header for v1/v2
reports and v2 leaves and from the first group record for v3, and
returns 0 for anything that is not IGMP so it goes on to the IP stack.
The message and record types have names now.
Storm control used meters 0 to 39, the same meters the ACL hands out,
so a storm limit and an acl meter could overwrite each other. It now
uses 24 + port * 4 + type, meters 24 to 63.
parse_storm() is no longer reentrant and uses plain locals, looks the
type up in a while loop and returns straight from the one-line cases.
storm_show() uses plain locals too.
The documentation says how IGMP decides between mcast and umcast, how
to get from a meter index to its limit, where the IFG bit of a meter
is, and what an ingress bandwidth limit on the same port does to the
storm limit.
The switch has no battery backed clock, only a seconds counter that starts
at zero on every boot. An SNTP client keeps UTC as the time of the last
answer plus the seconds counted since: "ntp server <name|ip>", "ntp interval
<minutes>", "ntp timezone <+hh:mm>", "ntp dst off|eu|us", "ntp on|off",
"ntp" and "time". A server given by name goes through the DNS resolver, an
answer from an unsynchronised server is ignored, and a failed attempt is
repeated after 30 seconds.
The local time adds the time zone offset and, while the European or United
States rule says so, one hour. The date is split with a shift and subtract
division and a walk over the years, so no 32-bit division from the library
ends up in the common area.
The System page gets the NTP settings and shows the local time.
A small resolver for IPv4 address records, so that clients such as NTP can
be given a host name: "dns server <ip> [<ip>]", "dns lookup <name>" and
"dns". Without a configured server it uses the one DHCP handed out. A query
goes to the servers in turn every two seconds and gives up after six tries;
answers with compressed names and CNAME records ahead of the address are
understood. A name that already is a dotted address is taken without a
query.
The resolver sits in BANK3, the command line in BANK2 next to the helpers it
uses. The System page shows and sets the servers.
The image rule no longer passes -p, so fileadder fell through to printing
html_data.h and html_data.c on stdout on every image build. The listing is
only useful when fileadder is run without an image, to see what it would
generate.
The .bin rule passes -p html_data to fileadder, which rewrites
html_data.c and html_data.h after the objects that include them have
already been compiled and linked. The next make therefore rebuilds
html_data.c, httpd.c and page_impl.c even when nothing changed, and
so does the one after that. The rule only needs to embed the files
into the image; the header comes from the html_data.c rule above.
Spotted by plaes in #358, which cannot be merged as it stands.
With this and the previous commit, a second make after a full build
compiles nothing, and the image is byte for byte the same as before.
Two things kept the same source from producing the same image.
fileadder walked the input directory with readdir(), which returns entries
in whatever order the filesystem hands them over. The same tree therefore
embedded the files in a different order on a different filesystem, and the
image differed byte for byte. scandir() with alphasort() fixes the order.
version.h was listed in .PHONY, which makes it permanently out of date and
propagates that to everything including it, so a plain build recompiled the
four largest translation units even when nothing had changed. Dropping it
from .PHONY alone would go too far the other way: with no prerequisites the
recipe would never run again and the version string would freeze at its
first value. A FORCE prerequisite keeps the recipe running every time, and
the generated header is only moved into place when its content actually
differs, so the timestamp survives an unchanged rebuild.
Measured on this tree: with FORCE the version follows GIT_VERSION and an
unchanged rebuild leaves version.h untouched; without it the header keeps
the value from the first build.
rtl837x_port.c prints "called" and "done" around mirroring, PVID, VLAN
and L2 setup, and dhcp.c around discover, request, start and stop. They
land on the console on every boot and config replay, and in the log
once syslog is running. The VLAN line keeps the VLAN, members and
tagged values, only without the function name in front.
On the KP_9000_6XHML_X2 this takes 359 bytes out of BANK1, 88 out of
BANK2 and 24 out of BANK3. BANK1 goes from 431 to 790 bytes free.
dhcp_addopt_request_ip() and dhcp_addopt_server_id() both end with a
copy of four bytes of our MAC to the current position, without moving
the position on. The next option always starts there, so those bytes
are written over before the packet goes out and never reach the wire.
The packet stays the same without the copy, and BANK3 is 102 bytes
smaller on the KP_9000_6XHML_X2.
ip_opt() copies four bytes whatever the option length says, so a
subnet, router, DNS, server id or broadcast option shorter than four
bytes stores the start of the next option as the address. long_opt()
does not look at the length at all and always moves on by six bytes, so
a lease, renewal or rebind option of another length puts the parser out
of step for the rest of the packet.
Both now read the length. An address or time shorter than four bytes is
skipped, a longer one is taken from its first four bytes and stepped
over whole, and a skipped time leaves the previous value alone.
Found in the code, not on the wire; no server here sends such options.
BANK3 is 47 bytes smaller on the KP_9000_6XHML_X2.
The main loop drains the NIC only after an RX interrupt, at most
RX_BUDGET frames, then clears the status and waits for the next one.
When frames are left and the buffer reaches the RX stop threshold, the
NIC takes no more frames and raises no further interrupt, so reception
stops for good.
Check the buffer after clearing the status and keep draining while it
holds data; the interrupt is re-enabled only once it is empty.
rtl8224_enable() waits 2.5 s after releasing the RTL8224 reset before
anything talks to the PHY. On an SWTGW218AS the chip id already reads
back 0x8224 at the first poll, about 265 ms after the release.
Remember when the reset was released and, once SMI is up, poll the chip
id until it answers, giving up after the same 2.5 s as before. The PHY
writes that follow read back the same as before.
The reset pulse before it goes from 0.5 s to 20 ms, twice the 10 ms the
related RTL8372 and RTL8221B need. The pulse does reset the chip: the
MDI reverse register (MMD 30, 0x0a90) still reads its power-on value
0x00f3 just before the init writes 0x00fc, as it does with 0.5 s.
Together the console banner comes 3 s sooner.
The SerDes write loop in phy_config_8224() waited on the busy bit with
no limit, so a PHY that never answers stopped the boot before the
network came up. Bound it and report a timeout.
The name branch read the fourth word without checking that the line had
one, and the tokenizer does not reset unused word slots, so "port 5 name"
took the name from wherever the previous command's fourth word had been:
"port 5 name hello" followed by "port 5 name" gave "hello" again, and
after a longer line it gave the tail of that line. The web UI never sends
the form, the console can. With no argument the name is now empty, which
also gives the console a way to remove a name.
The receive interrupt was wired up but never used: EX1 was enabled, the
handler re-enabled itself and did nothing, and the mask bit for it in the
NIC stayed clear, so idle() read the receive buffer register on every
pass to find out whether a packet had arrived, and slept until the next
tick when none had. A packet that arrived during that sleep waited for
the tick: 2.2 ms on average, 5 ms at worst, for every frame the CPU
handles.
Now the handler latches rx_irq and masks itself, and idle() sleeps
unless a receive, a link change, a console command or the tick is
pending. On rx_irq the loop drains the buffer, clears the status bit and
re-enables EX1, in that order: the NIC holds the line as long as the
status bit is set, and the bit does not clear while the buffer still
holds a frame, so a frame that lands between the last read and EX1 = 1
raises the interrupt again rather than getting lost. The other order,
clearing before draining, left the line asserted and produced an
interrupt on every pass. The mask is written after nic_setup(), which
resets it.
Measured on an RTL8373 board with the same counters in both images,
clocked by the tick counter, traffic from a host behind an LACP trunk:
```
polling interrupt
idle, register ops/s 788 79
25 pps, RTT avg/max 2.19/4.96 0.44/0.75 ms
500 pps, RTT avg/max 2.78/5.06 0.39/5.40 ms
500 pps, loss 0.08% 0.08%
```
The handler compiles to clr EX1 / setb rx_irq / reti.
The timer interrupt now raises a tick flag too, so idle() no longer works
out TICKS_DUE twice per pass, and cmd_available moves from xdata to a
bit. The four wake-up flags sit in the low bits of one byte at 0x20, so
the sleep test is a single read of that byte. tx_buf_empty deliberately
stays out: it is 1 when there is nothing to do, so including it would
keep the sleep test from ever firing.
idle() ran everything on every pass: the seconds block, the SFP pin
test, the TCP periodic timer behind a gate of its own, the STP timers
behind theirs. The timed work moves into handle_tick(), which idle()
calls once per system tick from a single gate; handle_tx() loses its
private one.
handle_sfp() ran on every pass as well, two GPIO reads per pass to learn
that nothing changed; it now runs every ten ticks. A module inserted is
still seen within 50 ms, and the read itself has been off the loop since
the wake-up wait moved to the tick.
No change in behaviour otherwise: the link, receive and console paths
stay where they were. SWTGW218AS: code +45 B, xdata +1 B, stack
unchanged.
The health checkpoints follow the work they measure: the seconds block,
SFP, TX and STP phases are taken inside handle_tick(), the link, RX and
command phases in idle().
The link-change interrupt was set up at boot (mode 0x5f84, mask 0x5f34)
but never enabled: the handler did nothing and did not clear the event in
the switch, so EX0 stayed commented out and idle() read the two link
registers on every pass instead, 400 reads a second on a quiet switch.
The handler now only latches a flag and masks itself; the register access
macros build a write in the shared SFR data bytes, so an interrupt that
touched the switch in the middle of a write from the main loop would
corrupt it. idle() clears the event register (write-one-to-clear, 0x3ff
for the ten ports), re-enables EX0 and then reads the link state, in that
order, so a change that lands during the read raises a new edge. The flag
is also set once a second from the seconds block, so a board whose INT0
line turns out not to be wired keeps detecting link changes, a second
late at worst. Boot drops the events pending from bringing the links up
before the mask is set.
Measured on an RTL8373 switch before this change: 0x5f88 held 0x3fd, nine
ports had reported a change nobody read. With the change a counter in the
loop went 2 -> 3 -> 4 on "port 5 off" / "port 5 on" and stayed at 4 over
three reads without events, so the event is delivered, cleared and
re-armed, and there is no flood.
SWTGW218AS: code +57 B, xdata 0, stack 151 -> 150 B; the flag is a bit
variable. The handler compiles to clr EX0 / setb link_irq / reti.
idle() also keeps in a bit what it saw in NIC_RX_BUFF_DATA when deciding
whether to sleep, and the first iteration of the receive loop uses it
instead of reading the register again a moment later. Between the two
only the link check and handle_sfp() run, and neither can make a queued
packet disappear. Every later iteration reads the register as before, so
the budget loop behaves as it did. This part was not measured on
hardware: one register read per pass needs a throughput run to show up.
SWTGW218AS: BANK1 and BANK2 +6 bytes each, BANK3 unchanged.
stp_timers() ran every fourth pass of the main loop and stp_clock counted
passes, which only measures time while a pass is one tick long. It never
quite was: a pass is as long as the packets it handles, and #482 now takes
up to four of them, so under an IPv4 stream a pass is about 16 ms and STP
time runs at a third of its rate, with hellos 6 s apart and a root aged out
after a minute. Since #483 the loop also stops sleeping while packets wait,
so under a flood of cheap frames passes come faster than ticks and STP time
runs fast instead, shortening the forward delay in exactly the situation a
loop produces. uip_periodic() had the same problem from the other side: it
ran once per pass, so the retransmit timer sped up with the loop.
Both now go by the tick counter the timer interrupt keeps. The STP block
catches up on ticks a long pass missed, at most eight steps at a time, and
handle_tx() runs its periodics once per tick at most. One byte of xdata
more, 48 bytes of code.
A host test drives the gate with one pass every 5 ms, every 16 ms and
every 0.6 ms for ten seconds each; the STP clock lands on 500 steps in
all three, where counting passes gave 156 and 4166. A pass of 1.3 s loses
time rather than firing 65 steps at once, and the arithmetic survives the
tick counter wrapping.
The advertisement written for a forced speed of 1G and above is 0x1001,
while auto and the forced 10M and 100M modes all carry bit 10, the PAUSE
capability. Forcing a port to 1g or faster therefore takes pause off the
link: the advertisement narrows and the far end has nothing left to
agree to.
Measured on a SWTGW218AS through phyget and physet, on a port with no
link so nothing was disturbed. Auto reads 0x15e1, port 1 1g reads
0x1001, port 1 auto reads 0x15e1 again, and writing 0x1401 by hand
sticks. That bit 10 is the pause capability follows from a second
reading: two ports advertise the same 0x15e1 from this side, and pause
is active only against the partner whose own advertisement carries the
bit.
Reported by feelfree69 in #489.
The .d files track headers, so adding or removing a flag on a tree that
was already built leaves every object that did not change for some other
reason compiled with the old flags, and the image ends up a mix of the
two.
How that shows depends on the flag. DIAG=1 fails the link on undefined
symbols, which at least stops the build. An opt-in whose hooks expand to
empty macros loses the calls instead, so the link succeeds and the
feature quietly measures nothing.
Objects now depend on a stamp holding CC_FLAGS, rewritten only when the
flags differ, so an unchanged flag set still does not force a rebuild.
Two per-port MAC status registers that nothing in the firmware reads:
0x6408 says which end is master on a BASE-T link, 0x63FC and 0x6400 say
whether pause was negotiated in each direction. port <n> show prints
both at the end.
The read sits in rtl837x_port.c rather than phy_show(), because these
are MAC registers and phy_show() is skipped for SFP ports. Master/slave
keys off machine.is_sfp[] so it stays off the fibre ports, where the
notion does not apply.
Bit N of each register is chip port N, which is not how
RTL837X_REG_LINKS_STS indexes its bytes a few lines above in the same
header.
edc469f made max_upload count, which bounds how many bytes a request may
carry. Nothing bounds where those bytes land. The two are not the same
check: the first watches the request, the second watches the flash address.
uptr walks forward one page at a time from FIRMWARE_UPLOAD_START and has no
ceiling. A body whose closing boundary never arrives keeps writing page after
page past the staging region, and on a flash exactly twice FIRMWARE_UPLOAD_START
the address wraps onto the running image at zero, so a bad upload takes the
working firmware with it. That commit's own message notes the related hazard:
flash_write_bytes() carries the address in three bytes and drops what does not
fit.
Bound it where uptr actually moves: refuse the next page once it would leave
the area check_and_flash_update_image() reads back, and answer 400. A partial
image left behind is harmless - boot rejects it on CRC and erases it.
This rebase drops the part of the original patch that removed max_upload;
the length limit and the address limit now sit side by side.
The counters, the phase hooks in idle() and the "health" command are now
behind HEALTH, set from the command line with HEALTH=1. Without it the
hooks are empty macros and the command does not exist, so a default build
carries none of it: on SWTGW218AS that is 1065 bytes of bank 2, 101 of the
common segment and 28 of xdata, plus seven banked calls per main-loop pass.
It is a developer's tool. Reading the dump takes knowing the main loop, and
a user who needs it for a report can build with the flag on, which is how
the kernel treats its lock and latency instrumentation as well.
The tcp slot dump printed the slot index behind `if (UIP_CONNS > 1)`, and
with one connection configured that is a constant-false condition around
live code: sdcc reported two "unreachable code" warnings for the body and
one "conditional flow changed by optimizer" for the loop that could only
run once.
Print the single slot directly and state the assumption as a build-time
check, so a build that raises UIP_CONNS fails loudly here instead of
quietly labelling every line as slot zero. Builds warning-free again.
What each line of the dump means, how two dumps give rates, and the
two things worth knowing before trusting the numbers: the command
inflates its own cmd phase counters by the cost of printing, and the
untouched figure is a high-water mark, not a live level.
Every probe of a misbehaving switch so far measured it from the
outside. This puts the witnesses inside.
Each idle() pass increments a loop counter and stamps a checkpoint
after every phase: link polling, SFP, RX, TX, STP and the command
dispatch. A phase spanning two or more system ticks counts as slow and
its worst time is kept, in 5 ms units. handle_rx counts frames, so the
dump separates a flooded CPU from a stalled loop.
At boot the free stack area is painted, preserving the interrupt state
around the painting, and the dump reports how much of the pattern
survives next to the live stack pointer. The TCP connection table is
printed whole: state, timers, retransmissions, ports and peer, next to
the httpd transfer state, so a permanently occupied slot names its
occupant. With more than one slot configured every slot is listed.
Everything is raw hex; two dumps a known time apart give the rates.
The implementation sits in cmd_parser next to the other command
handlers and needs no storage beyond its counters.
handle_sfp() called sfp_module_read() as soon as it saw a module appear, and
that path opened with delay(100). delay() spins on PCON until the tick counter
runs down, so the main loop stood still for 100 ticks - half a second at
SYS_TICK_HZ 200. Nothing else ran in that window: no STP, no LACP, no packet
handling. A diagnostic build measured the sfp phase at up to 107 ticks, the
longest stall of any phase in the loop.
Remember when the module showed up and let the loop continue. The I2C read
happens on a later pass, once the wake-up period has elapsed. Pulling a module
cancels a pending read, and a failed read still restores the detect bit, so the
existing retry-on-the-next-poll behaviour is unchanged.
The comparison is written out rather than using a helper so that this does not
depend on anything outside the current tree. The pending flag is an array
indexed by slot, like the other per-slot state in this file.
Cost on SWTGW218AS, measured against the branch point: BANK3 11173 -> 11264,
CSEG, BANK1 and BANK2 unchanged, plus 4 bytes of xdata.
idle() went to sleep before it looked at the receive buffer, so a packet that
arrived just after the loop dozed off waited for the next tick before anything
touched it. Every TCP round-trip paid that toll, which is why the web UI felt
sluggish even though no phase of the loop was anywhere near busy.
Check the receive buffer first and only sleep when it is empty. The read takes
its result straight from SFR_DATA_U16 rather than going through reg_read_m()
and the sfr_data[] copy, which is what the rest of the tree already does.
Measured on SWTGW218AS with this change alone:
web UI, median of 15 requests for the main page 88 ms -> 76 ms
CPU port under a one-way UDP stream 159 -> 230 packets/s
The loop still sleeps normally when there is nothing to do, so this does not
turn the core into a busy-wait: loops/ticks stays at 0.99 on an idle switch,
and rises above 1.0 only while packets are actually queued.
Costs 12 bytes of code and no extra XDATA.
handle_rx() picked up exactly one packet per iteration of the main loop. Since
the loop sleeps until the next tick, that capped the CPU port at roughly one
packet per tick no matter how little work it had to do. A burst of broadcast,
ARP or IGMP traffic aimed at the CPU queued up behind that and pushed out the
STP and LACP timers.
Drain up to RX_BUDGET packets in one pass instead. The budget matters: without
one a sustained flood would spin here and starve everything else in the loop.
The two register reads in the loop take their result straight from
SFR_DATA_U16 rather than going through reg_read_m() and the sfr_data[] copy,
which is what the rest of the tree already does.
Measured on SWTGW218AS with a one-way UDP stream, counting the packets the CPU
actually processed, with this change alone:
before 159 packets/s
RX_BUDGET 4 245 packets/s, loop iteration ~16 ms
RX_BUDGET 8 298 packets/s, loop iteration ~26 ms
Throughput is already most of the way there at 4, so the larger budget mostly
buys a longer worst-case delay for the other phases. STP stayed responsive in
both cases.
Costs 71 bytes of code and no extra XDATA.
The TODO next to the disabled TCP checksum code asks which bit of the RX tag
carries the result. It is bit 2 of byte 1: the hardware sets it when the L4
checksum is bad.
That answers the question for UDP as well, which was not being checked either
because UIP_CONF_UDP_CHECKSUMS is 0. Both paths now read the flag instead of
running a checksum over the payload on the 8051.
A zero UDP checksum, which is optional in IPv4, is not flagged by the hardware,
so DHCP keeps working and no extra condition is needed.
rx_headers lives in rtlplayground.c, which the host tests do not link, so
test_httpd_tx carries the storage itself the way it already carries uip_buf.
A zeroed descriptor reads as a good checksum, so the existing scenarios are
unaffected.
A new scenario sets the flag on a request and expects it counted as a checksum
error and left unanswered, then sends the same request with the flag clear and
expects it served. Built against uip.c without this change, those first two
checks fail and the two control checks still pass, so the scenario tells the
two versions apart rather than merely exercising the code.
Costs 156 bytes of code on SWTGW218AS and no extra XDATA.
The row sits between Hardware and Flash. The firmware sends the formatted string
rather than the raw register, since the System table prints its values as they
arrive.
Costs 186 bytes in BANK1.
The chip has a pair of thermal meters and nothing was reading them. This adds a
`temp` command that prints the current reading next to the one taken at power-on.
The result register at 0x340 splits a 19 bit value across two fields: bits 18:3
live in the low 16 bits, bits 2:0 in bits 18:16, with the sign at bit 18, degrees
in 17:10 and a fraction below. The nice part of that layout is that the degrees
fall out of a shift of the low half, so the conversion stays 16 bit.
The meter comes out of reset latched: the register keeps whatever was measured
when the board powered up and then never moves. Four samples 40 s apart came back
identical down to the raw ADC, and 0x340 matched the power-on register at 0x350.
Clearing bit 2 of the control register at 0x338 during init is what makes it live.
Measured on an SWTGW218AS: 58.7 to 59.5 C while running, with the power-on
register still showing the 49.2 C it started from. For what it is worth, the
scale lines up three ways: the threshold register reads -40 and +125, the slope
from warm-up works out at 4450 LSB/C, and the slope between the two meters at
4388 LSB/C.
We only read the meter that is up after boot. The other sits in reset with no
coefficients, so it would just repeat its power-on value.
Costs 231 bytes in BANK2.
The helper landed between that comment and the function it describes, so the
comment now reads as if it belonged to name_char(). Moving the helper up puts
the two back together. The generated code is unchanged.
gcc flags the else whose only statement is dbg_string(), because that macro
expands to nothing unless DEBUG is on, leaving the branch with an empty body.
The line is older than this branch; the bench is simply the first thing that
compiles httpd.c with a host compiler and -Wall -Wextra.
Turn warnings into errors in the test Makefile too, so the next one is caught
where it appears instead of scrolling past. It is the only warning the four
test binaries produce, so nothing else has to change.
The replay takes a line of at most 126 bytes, so a longer one is skipped
on boot. Neither the upload path nor the editor looked at line length,
so the file the user saved was not the configuration the switch would
come up with.
Reject such a body in config_take(), before the sector is erased, which
the upload path already maps to 400. The editor points at the offending
line and its length, and measures it in bytes rather than characters, so
a name written in a non-ASCII script is counted the way the switch
counts it.
execute_config() replays the saved configuration line by line into
cmd_buffer. A line that does not fit, or one cmd_tokenize() rejects,
ended the replay right there: everything below it was silently left
unapplied, while the file itself and the editor showing it stayed
complete. On a switch here, a 130-byte line placed after the last real
setting was enough to lose every line that followed it on the next boot.
Report the offending line and carry on with the next one. The skip flag
lives across the flash page refill, so a long line that crosses a page
boundary is not resumed halfway and run as a truncated command.
Drives the unmodified httpd.c and uip.c through a handshake and a GET
from a client that moves its receive window, and compares the bytes that
reach the wire with the file they are meant to carry. The served file
holds a position-dependent pattern, so a repeat or a gap is reported at
its offset rather than as content that differs somewhere.
The first scenario holds the window still and must pass: it is the check
that the bench itself is sound, before the two moving-window scenarios
are believed.
uip_mss() is the limit on the next segment, not a record of the last
one: uIP recomputes it from the window the peer advertises in every
incoming segment, before the application is called. The ACK path
subtracted it from slen and added it to o_idx, and the retransmit path
handed it to uip_send(), so whenever the window moved between a segment
going out and its ACK coming back, the file being served lost or
repeated the difference. A window shrinking from 1460 to 600 between the
two repeats 860 bytes under fresh sequence numbers, which a browser
writes into the file; a window opening the same way skips 860.
Remember the length in tx_send() and use it in both places. The
retransmit path then repeats exactly the segment uIP still counts as
outstanding, which is what uip_connr->len makes it put on the wire.
uip_appdata is void *, so p - uip_appdata subtracts pointers of
different types. SDCC accepts it, C does not, and no host compiler will
build the file for a unit test. Cast to the type the byte count is meant
in; the generated firmware code is unchanged.
The vendor, model and serial strings are filtered while the EEPROM read
fills the buffers, so the page copies them out as they are. NUL still
ends a string, so a field shorter than its slot reads the same as before.
The three loops in send_status() become one call each. strcpy() cannot
return the length: rtl837x_common.h hides that prototype under
RTLP_HOST_TEST so host builds take the C library version, and a call
that adds its result to slen does not compile there. A small static
helper does the copy instead, and bank 1 drops by 96 bytes.
The console, POST /cmd and the saved config all go through the command
parser, so one filter there covers every way a name can be set. The
hostname already did this inline; port and VLAN names now do it too.
The SFP strings still need escaping on the way out: they come from the
module's EEPROM, not from a command.
A port named NAS"1 made status.json unparsable, so the page stopped
loading, and the name survives a reboot in the saved config. VLAN names
and the SFP strings have the same problem.
They now go through a helper that replaces ", \ and non-printable bytes
with a dot, the way the hostname is already sanitized on ingest. The
length does not change, so the size checks still hold.
The helper also covers the 0xa0 byte that send_sfp_info() skipped as a
special case, so that check is gone.
Compiling these two files for the host turns up warnings that SDCC does
not print: four places mix & with | and two mix && with ||, and l2_delete
keeps a counter it never reads. The parentheses only say what the
compiler already does, so the generated code is unchanged.
counter_to_html() reads the SFRs directly for the zero test, which saves
14 bytes of bank 1.
page_impl.c and rtl837x_port.c are linked together over the simulated
engine, so /vlan.json, /vlanlist and /l2.json are checked against what
vlan_create, pvid and the L2 table hold, through the same bytes the switch
would. The L2 walk is driven the way the web page drives it, page after
page until an index repeats, which is also where the repeat of the first
entry is pinned down as the wrap marker the page relies on. The counter
test fails on the code before the previous commit.
send_status wrote the high and the low word of a packet counter one after
the other, each without its leading zeros. That reads fine until a port
passes four billion packets; from then on a low word of 5 prints as "0x15"
next to a high word of 1, and the rates the page derives from the
difference between two readings jump around. send_counters already padded
the low word, so both now share one helper that pads it only when the high
word is set, which also drops the leading "0" the counters page used to
print in front of every small value.
The switch is reached through four register functions and the SFR_DATA
registers, so a flat register file behind them is enough to run the table
code on the host. A few addresses are live: writing TBL_CTRL with EXECUTE
performs the VLAN or L2 operation at once and clears the bit, STAT_GET
fetches a counter, L2_TBL_FLUSH_CTRL drops entries. Nothing ever reports
busy, so a polling loop runs once and the tests say nothing about what
happens when hardware stalls; that question was settled elsewhere.
The header states the VLAN and L2 entry layouts on its own, so a test can
hold what rtl837x_port.c writes against a second reading of the same bits
rather than against itself. The first suite does that for the VLAN entry,
the PVID register two ports share, the static multicast and management
entries, the per-port flush and the trunk registers. Two stub headers stand
in for the ones a firmware build generates, so the harness needs no SDCC
build first.
Two things kept every register-driven module out of the host harness. The
SFR keywords were unknown, so rtl837x_sfr.h did not compile at all, and once
it did, each translation unit would have defined its own copy of the
registers. They map to extern declarations now; a mock emits the storage
once by re-including the header with the keywords redefined.
The other was memset. rtl837x_common.h hides the firmware's own prototypes
under RTLP_HOST_TEST so host builds use the C library, but nothing declared
the library versions, and the modules do call them. The shim pulls in
string.h ahead of everything, where nothing can clash with it.
The messages said Error: themselves, or usage:, or nothing at all.
cmd_error() prints the prefix now, so every rejected command answers the
same way and the strings only carry what is specific to them.
Two messages that started with Error or refusing are reworded so the
prefix does not read twice. The syslog usage text becomes one string
instead of three calls.
run_cmd_body() answers POST /cmd with 400 when err_status is set, but
only the tokenizer set it. Every "Error:", "Invalid ..." and "Unknown
command" from the parsers went back as 200, so the web page reported the
command as applied, and save_cmd put the rejected line into the command
history, from where Save to flash wrote it into the startup config.
Set ERR_INVALID_ARGUMENT on every path that rejects a command: the err:
labels of the parsers, the parsers that print their own error, the
stp parser and the unknown command fallback. Warnings that still apply
the command, such as a full VLAN name table, are left alone.
Record a command in the history only when it was accepted, and let
execute_commands() report the first failure of a multi-line body, since
cmd_tokenize() clears err_status again for every following line.
Save to flash ran the stored config through the same filter as the
command log, so stored lines the page does not know were dropped. The
stored lines are now carried over as they are and only the log is
filtered.
ingress only changes the ports it lists, but the merge replaced every
stored ingress line. It now merges per port; "ingress t|u|a" still
replaces everything, and per-port settings an all-ports line already
overrode are not revived.
Write from the config editor no longer clears the command log or the
unsaved marker, since the edited text does not hold the changes made on
other pages; only Save, which merges them, clears the log.
The command log grows from 1 kB to 2 kB, which still fits the 2500 byte
output buffer, and send_cmd_log() stops at the end of that buffer.
The workflow only ran on push, so a pull request opened from a fork
never got a build, and neither did the host-side unit tests that run in
the same job.
handle_post() takes the request path from byte 6 of the segment it is
given. For the first segment of a POST that is the path, but for a later
segment of a multipart upload it is whatever part of the file happens to
sit there. The cmd and login handlers were matched before the multipart
state was checked, so a segment of a config or firmware upload with
"cmd " at that offset ran the rest of the segment as CLI commands, and
one with "login " there aborted the upload with 400.
Check for an upload in progress, and for new upload and config requests,
before looking at cmd and login. A new POST cannot match both sets of
words, so nothing changes for requests that are not uploads.
session_id is cleared at boot and only a successful login fills it in,
while the uptime counter and last_session_use both start at 0. For the
first SESSION_TIMEOUT seconds after a start, a request carrying an empty
"Cookie: session=" therefore passes is_word_x(session, session_id) and
is treated as logged in, which is enough for /cmd, /config and /upload.
Only look at the cookie once a session has been handed out.
flash_read_security() ends its loop the same way flash_read_bulk() did
before the previous commit: only through comparisons with 1, 2, 3 and 4. A length of
zero matches none of them, the following subtraction wraps on uint16_t
and the loop keeps printing until the counter comes back down to 4.
No caller passes zero today, since the only one is the CLI with a
constant length of 40, but the bound belongs in the function rather
than in whoever calls it.
flash_read_bulk() ends its copy loop only through the comparisons
len == 1|2|3|4, so a length of zero matches none of them. The
following len -= 4 wraps on uint16_t to 65532 and reaches 4 only
after 16384 iterations, writing 65536 bytes to the destination and
overwriting the whole XDATA space.
send_config() gets there with valid_len 0 whenever the stored
configuration begins with a NUL byte, which is the state left by
uploading an empty configuration file. Every later request for the
configuration page then clears the management VLAN and the STP
flag and replaces the host address, while the switch keeps running
and keeps forwarding traffic.
The 8051 in the RTL837x has 48 kB of XDATA, 0x0000 to 0xBFFF. Writing
a byte and reading it back from the same address works all the way up
to 0xBFFF on a SWTGW218AS, while at 0xC000 the byte comes back as 0x00.
Without --xram-size the linker assumes 16 MB, so running past the end
would still build cleanly and only show up at run time.
The value is 49151 rather than 49152. The linker check adds up the
sizes of the XDATA areas, and XDATA allocation starts at 0x0001, so a
limit of 49152 would still let the last byte land on 0xC000.
boot.c calls it from BANK3 and only rtlplayground.c had a prototype, so
the compiler saw an implicit declaration. The call itself was fine, the
function lives in the common area, but the warning was real. Move the
prototype into the shared header.
Reported by vDorst.
sfp.c takes handle_sfp, sfp_module_read, sfp_apply_quirks, sfp_get_info,
sfp_read_field, sfp_print_info, setup_sfp_gpio, the quirk table and the module
state that goes with them. Everything exported is __banked: handle_sfp() and
sfp_print_info() are reached from cmd_parser.c in BANK2, the rest from the
common area, and both are bank boundaries.
The quirk table needed checking rather than assuming. Its entries are __code
pointers, and a __code pointer carries no bank, so passing one to a function in
a different bank hands it an offset read through the wrong window. That is safe
here because strcmp() sits in the common segment at 0x51f and is reached with a
plain lcall, so the bank register still says 3 while it runs. Verified in the
built image: the table at 0x35580 holds 0x563c and 0x5644, which resolve to
"QSFPTEK" and "QT-SFP+-T" inside BANK3.
Common segment 13393 -> 8432 bytes, leaving 7492 free rather than 2531. BANK3
holds 5710, BANK1 is unchanged and BANK2 grows by 31 for the trampolines.
All 34 machines in machine.h build and link, and the same walk over the
generated assembly finds no plain lcall crossing a bank boundary.
The common segment is the scarce one: sixteen kilobytes shared by every bank,
and before this it had about 2.5 kB left. Most of what moves here runs once at
startup and does not have to sit in it. The two SerDes helpers are the
exception: the link-change handler and the SFP polling both reach sds_config()
while the switch is running, so they are not startup-only. None of it is
reached from an interrupt.
boot.c takes setup_i2c, init_smi, nic_setup, rtl8373_revision, rtl8224_enable,
early_boot_handle_button, set_hostname_default and the two SerDes helpers.
BANK3 is enabled with the linker flag; nothing else in the build needed
changing.
Everything moved is declared __banked, since every caller is outside BANK3:
main() and friends run from the common area and rtl837x_init.c calls
sds_config() and sds_config_mac() from BANK2. The calls the moved code makes
outward were already banked, so that side needed no work.
Common segment 13393 -> 10137 bytes, leaving 5787 free rather than 2531.
BANK3 holds 3732. All 34 machines in machine.h build and link. Walking
the generated assembly for plain lcalls that cross a bank boundary finds none
among 2808 calls; those build cleanly and only fail at run time, so it seemed
worth checking by machine rather than by eye.
IPBUF is laid out for frames we send, with the 12 byte TX descriptor in
front of the Ethernet header. A received frame starts with the Ethernet
header at uip_buf[0] and carries the RTL and VLAN tags after the
addresses, so IPBUF->ethhdr.src read the port mask and both VLAN fields
as a MAC. Every IP packet from the local network then replaced the
sender's ARP entry with that, and our replies went to an address nobody
has. The IP source address sits at the same offset in both layouts,
which is why the rest looked right.
Use BUF, the receive view uip_arp_arpin() already works from.
The state literals were spread over eighteen places in the file, sixteen
of them older than this branch, so naming only the new ones would have
left it written half one way and half the other.
Naming them separates two roles the literal hid: 0b11 is the forwarding
state in a call and a two bit field mask in a read-modify-write, hence
both STP_ST_FORWARDING and STP_ST_MASK. The comment above stp_state_set()
said what the defines now say, so it goes.
stp_parse() holds an entity index, not a port. cmd_parse_port() has
already mapped the front panel digit through machine.phys_to_log_port[],
and the aggregates continue that same logical range above the CPU port,
so call the variable ent. Reading the two branches of the if no longer
means following the parser two functions down.
No change to the generated code: 5331 instructions before and after.
The web UI became one index.html plus one main.js while this branch was
open, so the STP page changes had no html/stp.js and html/config.js left to
live in. They are re-applied here against the new structure.
A row now carries two derived fields: the name the CLI expects for it
("port N" or "lag N") and the key its controls are keyed by (the port
number or "LN"). A group's row is labelled with its front panel members,
which /stp.json reports in the mbr field.
conf_cmds and conf_overwrite accept the "stp lag N ..." forms so the
startup config keeps them.
Review of #397 pointed at the bare 10, which shows up in fifteen places. It
is the width of the port field in the MSTP register, so it is the CPU port
index plus one and it gets a name.
The web page counted to ten as well when listing a group's members. It uses
numPorts now, like the rest of that page does.
The aggregation section of the doc no longer names the OEM firmware or calls
a group a trunk, and it says plainly that the hardware keeps no per-group
state, so the firmware writes the members itself.
Generated code is unchanged: the only difference in the assembly is the
version string.
Spanning tree so far saw only physical ports. Two ports aggregated towards
the same neighbour look to the protocol like two parallel paths, so it
blocks one of them and cuts the group in half.
Give each of the four groups an STP entity of its own, numbered above the
physical ports. A member port answers to its group: BPDUs arriving on it
are accounted to the entity, the entity's state is written to every member
together, and its BPDUs carry the state of a live member. Ports outside
any group keep behaving exactly as before.
Membership comes from the aggregation tables once a second; when it
changed, the entity's state is reapplied to the new set of members. The
CLI takes lag <1-4> wherever it takes port <n>, the web UI shows a group
as one row, and the saved config keeps the lag form of the commands.
The lookup tables live in BANK1, so the routine switches the code bank to
reach them with movc and never switches it back. That is the contract the
__naked declaration already implied: same bank or common segment only.
The name now says it.
crc16_bank1 is the routine unchanged. crc16 becomes a __banked wrapper in
BANK1, so a caller from another bank has its own bank put back by
__sdcc_banked_ret. The two existing call sites take the direct path and
pay nothing.
A VLAN name is copied into vlan_names with nothing checking vlan_ptr
against VLAN_NAMES_SIZE. The only limit is the 128 byte command line, so
enough named VLANs walk straight off the end of a 1 kB table.
What sits immediately behind it makes this worse than a plain overflow: at
0x048A comes vlan_ptr itself, the index driving the write, then port_names
and cmd_buffer. Once the index is corrupted the following writes land
wherever it now points, and the configuration is replayed at boot, so a
config file that overflows does it again on every start.
Measure the name first and refuse it if the three id digits, the name, its
separating space and the terminator would not fit. The check goes before
vlan_name_remove() so a name that does not fit cannot take the existing one
with it, and the VLAN still gets its ports: dropping the whole line would
lose port membership during a config replay, which is worse than losing a
name.
The copy walks a pointer instead of indexing vlan_names[vlan_ptr++] each time,
and the word offset comes out of cmd_words_b once. Writing the bound as
VLAN_NAMES_SIZE - 5 folds the constant at compile time instead of adding it on
every call. BANK2 ends up 25 bytes smaller than it was before the check
existed.
The RTL tag carries a 4-bit port number for received frames, and the two
places that turn it into a mask bit take the whole byte:
entry.pmask |= (1L << (IGMP_I->rtl_tag.pmask >> 8));
The comment beside it already says only the low four bits count, but nothing
takes them. rtl837x_stp.c:424 does the same extraction and does mask:
stp_scratch = ((uint8_t)HTONS(STP_I->rtl_tag.pmask)) & 0x0f;
With a count above 15 the result is not a bit at all. SDCC narrows the 1L to
16 bits and emits the shift as a djnz loop, so a count of 200 spins the loop
200 times and leaves zero behind: the join adds no port and the leave clears
none, neither saying anything. It also spends those iterations inside packet
handling.
Mask to four bits and shift a uint16_t, which is the width the surrounding
code works in. Six bytes of BANK1.
Worth saying that this does not make snooping work on its own. struct
igmp_pkt has no vlan_tag field while struct eth_in describes the same frame
with one, so every IP and IGMP field below rtl_tag is read four bytes early.
The 100M branch of phy_set_speed() was missing an else. A port set to 100M
half wrote 0x1481, walked into the next if, found duplex was not 1, took its
else and overwrote the register with 0x1581 straight away, so it advertised
100BASE-TX half and full both. That is what asking for both is meant to do,
and forcing half is something people do to match a partner that cannot
negotiate, so the link comes up looking fine and misbehaves under load.
Bit 7 is 100BASE-TX half and bit 8 is full, which makes 0x1481, 0x1501 and
0x1581 half, full and both, the same shape as 0x1421, 0x1441 and 0x1461 in
the 10M branch above.
Both branches now choose the advertisement into a variable and write it once,
and they compare against the PHY_DUPLEX_* names instead of 0, 1 and whatever
is left. Same values reach the PHY; BANK2 loses 92 bytes.
The 100M branch of phy_set_speed() is missing an else. A port set to 100M
half writes 0x1481, falls into the next if, finds duplex is not 1 and takes
its else, and immediately overwrites the register with 0x1581. The port
ends up advertising 100BASE-TX half and full, which is what "both" is
supposed to mean.
The 10M branch directly above has the chain the 100M one meant to have, and
the values line up with it: bit 7 is 100BASE-TX half, bit 8 is full, so
0x1481, 0x1501 and 0x1581 are half, full and both, exactly as 0x1421,
0x1441 and 0x1461 are for 10M.
Forcing half duplex is something people do to match a link partner that
cannot negotiate, so quietly advertising full as well is the wrong way for
this to fail.
Not tried on hardware: every port on the switch here has a link up, and
setting the speed restarts negotiation.
isr_ext2() ends with PCON |= 1, putting the core to sleep from inside an
interrupt handler.
The DW8051 leaves idle when any enabled interrupt is activated, so the core
does not stay down for long. It naps until the next enabled interrupt request
turns up, with the 200 Hz system tick putting a ceiling of 5 ms on that, and
then carries on.
The sleep buys nothing either way, because the instruction after it is the
return. While it lasts the handler holds the priority latch, so everything at
its level or below waits, and that includes the tick, the console and the NIC
receive interrupt.
The handler still clears its flag, which is what it has to do. The bit numbers
beside the two masks were wrong: 0xef clears bit 4 and 0xdf clears bit 5,
not 7 and 6.
isr_ext2() ends with PCON |= 1, putting the core to sleep from inside an
interrupt handler.
The DW8051 leaves idle when any enabled interrupt is activated, so the core
does not stay down for long. It naps until the next enabled interrupt request
turns up, with the 200 Hz system tick putting a ceiling of 5 ms on that, and
then carries on.
The sleep buys nothing either way, because the instruction after it is the
return. While it lasts the handler holds the priority latch, so everything at
its level or below waits, and that includes the tick, the console and the NIC
receive interrupt.
The handler still clears its flag, which is what it has to do. The two wrong
comments next to the masks go as well: 0xef clears bit 4 and 0xdf clears bit 5,
not 7 and 6, and the masks already say that without help.
isr_ext2() ends with PCON |= 1. On the DW8051 any enabled interrupt request
ends idle, so the handler sleeps until the next request arrives, the system
tick at the latest, and only then returns. Everything at the same priority
waits with it, and the instruction after the idle is RETI, so the sleep buys
nothing.
The handler still clears its flag, which is what it has to do. The other four
uses of PCON |= 1 are in task context and are left alone.
A file larger than the output buffer is sent in two phases: the first
buffer goes out in MSS-sized pieces, with o_idx walking through it, and
what is left is then streamed from flash a chunk at a time into outbuf
from offset 0.
The continuation branch never reset o_idx, so it kept the offset the first
phase had left it at, while uip_rexmit() retransmits from outbuf + o_idx.
A lost continuation segment was therefore retransmitted as the bytes 1460
further into the buffer, which the client accepts as the missing data, and
with o_idx + slen past the 2500-byte buffer it also read whatever xdata
follows outbuf.
Reproduced on a SWTGW218AS by dropping 15% of the switch's TCP segments:
seven of eight fetches of a 21 kB static came back the right length and
the wrong content, each first differing at a fixed phase of the 1460-byte
chunk. With o_idx reset the retransmission repeats the chunk it sent.
The o_idx += slen right after slen = 0 went too: it added nothing.
(cherry picked from commit 789d29423288f89411a41673e26ce1854b296c3d)
uip_arp_ipin() is an empty macro with its body under #if 0, both inherited
from the uIP import and untouched since. That leaves uip_arp_update()
reachable only from uip_arp_arpin(), so an entry is refreshed only by ARP
addressed to us and ages out after UIP_ARP_MAXAGE no matter how much traffic
passed over it.
When it goes, the next transmission to that host hits the miss path of
uip_arp_out(), which overwrites the packet in uip_buf with an ARP request and
returns. For TCP that costs a retransmission. For UDP nothing retransmits, and
handle_tx() sends the UDP connections through uip_arp_out() too, so the
datagram is lost.
The body could not be enabled as written: uip_len -= sizeof(struct uip_eth_hdr)
is a leftover from when UIP_LLH_LEN was 0. Here it is ETHER_HEADER_SIZE +
RTL_FRAME_DESC_SIZE and uip.c reads the IP header at uip_buf[UIP_LLH_LEN], so
uip_len has to keep the link layer in it. The rest of the function is sound.
replaceCalls() ended with strlen(&buffer[pos]), so the length recorded for a
file was the distance to its first 0x00 byte rather than the file size. The
byte just past the content happens to be zero today, which is the only reason
the numbers come out right.
Nothing in html/ contains a 0x00 today, so this is latent, but it is a trap
waiting for the first gzipped or binary asset: gzip puts a zero in the fourth
byte of its header. A gzipped style.css lands in the index as 3 bytes, and
since addr advances by that same value the next file is placed 3 bytes in and
overwrites what came before it. Two gzipped files in html/ are enough to see
it: both come out as 3 bytes and the second sits 1356 bytes inside the first.
Pass the length in and return the adjusted one. The substitution shortens
#{function} to #{NNN}, so the delta is known without measuring. The loops are
bounded by the length as well, which also covers -n, where nothing had put a
terminator in the buffer for strlen to find in the first place.
No output change: the image built from an unmodified html/ is byte for byte
the same before and after, and html_data.h is identical.
Option 58 is optional, and dhcp_state.renewal is only ever written by
parse_opts(), so a server that leaves it out keeps it at zero. The ACK
handler then sets dhcp_timer to zero, and the callback treats a zero timer
in LEASING as time to renew, so it sends a REQUEST on the next pass.
That REQUEST does set a 30 second timeout, but the ACK that answers it
comes back through the same path and zeroes the timer again, so the two
sides trade REQUEST and ACK as fast as the round trip allows, with the
console printing the whole lease each time round.
RFC 2131 has the client renew at half the lease when the server does not
say, so use that, and fall back to a fixed value if there is no lease
either. Both only fill in a value that is missing: a server that asks for a
short renewal still gets exactly what it asked for, which a blanket lower
bound would have overridden.
Not reproduced here, that needs a server configured without the option.
write_char() masked writeptr and never looked at readptr, so once more
than LOGBUF_SIZE bytes were written between two drains the ring wrapped
over content that had not been sent yet.
That is not a corner case. The ring is emptied once per main loop pass,
while a single command runs to completion inside one pass, and a full L2
listing prints well over twice the 512 byte buffer. On hardware the whole
1227 byte dump came out as one 174 byte datagram whose first line began in
the middle of a MAC address.
Drop the character when the ring is full instead of overwriting, so what
has been logged stays intact and it is the tail that is lost. A full ring
also flags a line, otherwise a burst without a newline would leave the
reader waiting on line_available forever and syslog would stop for good.
d00f