Merge pull request #535 from DrDoof/fix/igmp-v2

igmp: handle IGMPv1/v2 reports and v2 leaves
This commit is contained in:
logicog authored and GitHub committed 2026-10-04 07:16:52 +02:00
commit 5ab247e996
4 files changed
+60 -23

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+6 -2
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@@ -69,7 +69,7 @@ The code currently provides the following functions:
void igmp_setup(void) __banked;
void igmp_enable(void) __banked;
void igmp_router_port_set(uint16_t pmask) __banked;
void igmp_packet_handler(void) __banked;
uint8_t igmp_packet_handler(void) __banked;
void igmp_show(void) __banked;
```c
`igmp_setup()` is called at boot-time and configures flooding of all IP-MC packets by
@@ -80,7 +80,11 @@ of IP-MC packets to be limited to only subscribed ports.
`igmp_router_port_set()`configures forwarding ports for IGMP messages.
`igmp_packet_handler()` implements handling of trapped IGMP packets by the CPU.
`igmp_packet_handler()` implements handling of trapped IGMP packets by the CPU. It is called
for frames to 01:00:5e:xx:xx:xx and returns 0 when the frame is not a trapped IGMP packet,
so that it is passed on to the IP stack. IGMPv1/v2 reports (0x12, 0x16) join the group given
in the IGMP header, IGMPv2 leaves (0x17) leave it, IGMPv3 reports use the first group record
(type 4 joins, type 3 leaves). Trapped IGMP frames arrive without a VLAN tag.
`igmp_show()` prints out the IGMP configuration on the CLI.
+44 -18
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@@ -9,6 +9,7 @@
#define IPMC_USES_L3MC
#include <stdint.h>
#include <stddef.h>
#include "rtl837x_common.h"
#include "rtl837x_sfr.h"
#include "rtl837x_regs.h"
@@ -19,6 +20,7 @@ extern __code const struct machine machine;
extern __xdata uint8_t igmpEnabled;
#include "uip.h"
#include "uip_arp.h"
#pragma codeseg BANK1
#pragma constseg BANK1
@@ -29,6 +31,13 @@ extern __xdata struct machine_runtime machine_detected;
extern __xdata uint8_t uip_buf[UIP_CONF_BUFFER_SIZE + 2];
__xdata uint16_t idx;
#define IGMP_IP_HDR offsetof(struct igmp_pkt, hlen)
#define IGMP_IP_IHL 0x0f
#define IGMP_GROUP_OFS 4
#define IGMP_V3_RECORD_OFS 8
static __xdata uint8_t igmp_grp;
static __xdata uint8_t igmp_join;
#ifdef IPMC_USES_L3MC
struct ipmc_table_entry {
@@ -198,8 +207,10 @@ void entry_to_l2mc(void)
#endif
void igmp_packet_handler(void) __banked
uint8_t igmp_packet_handler(void) __banked
{
if (IGMP_I->ipv4_tag != HTONS(UIP_ETHTYPE_IP) || IGMP_I->protocol != IGMP_PROTO)
return 0;
// By default we do not send anything out
uip_len = 0;
@@ -211,24 +222,40 @@ void igmp_packet_handler(void) __banked
}
write_char('\n');
#endif
if (IGMP_I->protocol != 2)
return;
igmp_grp = IGMP_IP_HDR + ((IGMP_I->hlen & IGMP_IP_IHL) << 2);
#ifdef DEBUG
print_string("Found IGMP, type: "); print_byte(IGMP_I->igmp_type); write_char('\n');
print_string("Found IGMP, type: "); print_byte(uip_buf[igmp_grp]); write_char('\n');
#endif
// We react to IGMPv1/v2 and v3 membership reports
if (!(IGMP_I->igmp_type == 0x12 || IGMP_I->igmp_type == 0x16 || IGMP_I->igmp_type == 0x22))
return;
switch (uip_buf[igmp_grp]) {
case IGMP_V1_REPORT:
case IGMP_V2_REPORT:
igmp_join = 1;
break;
case IGMP_V2_LEAVE:
igmp_join = 0;
break;
case IGMP_V3_REPORT:
igmp_grp += IGMP_V3_RECORD_OFS;
if (uip_buf[igmp_grp] == IGMP_V3_TO_EXCLUDE)
igmp_join = 1;
else if (uip_buf[igmp_grp] == IGMP_V3_TO_INCLUDE)
igmp_join = 0;
else
return 1;
break;
default:
return 1;
}
igmp_grp += IGMP_GROUP_OFS;
#ifdef DEBUG
print_string("IGMP membership report, type "); print_byte(IGMP_I->igmp_rtype); write_char('\n');
print_string("IGMP join "); print_byte(igmp_join); write_char('\n');
#endif
#ifdef IPMC_USES_L3MC
memset((__xdata uint8_t *)&entry, 0, sizeof(struct ipmc_table_entry));
// For IPv4 MC, the Source-IP is 0.0.0.0
entry.sip[0] = 0x00; entry.sip[1] = 0x00; entry.sip[2] = 0x00; entry.sip[3] = 0x00;
// For IPv4 MC, the Destination-IP is the IPv4 MC address
entry.dip[0] = IGMP_I->mc_ip[0]; entry.dip[1] = IGMP_I->mc_ip[1]; entry.dip[2] = IGMP_I->mc_ip[2]; entry.dip[3] = IGMP_I->mc_ip[3];
memcpy(entry.dip, &uip_buf[igmp_grp], sizeof(entry.dip));
entry_to_l3mc();
#else
/* The L2 Multicast MAC for IP-Multicast is 01:00:5e:xx:yy:zz, where
@@ -238,7 +265,7 @@ void igmp_packet_handler(void) __banked
*/
memset((__xdata uint8_t *)&entry, 0, sizeof(struct l2mc_table_entry));
entry.mac[0] = 0x01; entry.mac[1] = 0x00; entry.mac[2] = 0x5e;
entry.mac[3] = IGMP_I->mc_ip[1] & 0x7f; entry.mac[4] = IGMP_I->mc_ip[2]; entry.mac[5] = IGMP_I->mc_ip[3];
entry.mac[3] = uip_buf[igmp_grp + 1] & 0x7f; entry.mac[4] = uip_buf[igmp_grp + 2]; entry.mac[5] = uip_buf[igmp_grp + 3];
entry.vlan = 1; //TODO: Get this out of the packet and compare with VLAN table!
entry_to_ipmc();
#endif
@@ -286,7 +313,7 @@ void igmp_packet_handler(void) __banked
print_sfr_data();
#endif
idx = ((sfr_data[2] & 0xf) << 8) | sfr_data[3];
if (IGMP_I->igmp_rtype == 0x4) {// Join group
if (igmp_join) {// Join group
if (sfr_data[2] & 0x10) {
print_string("\nIGMP-Entry FOUND\n");
reg_read_m(RTL837x_L2_DATA_OUT_B);
@@ -297,7 +324,7 @@ void igmp_packet_handler(void) __banked
// Update (found) entry with portmask from trapped Packet
entry.pmask |= ((uint16_t)1) << ((IGMP_I->rtl_tag.pmask >> 8) & 0x0f); // Swap bytes from network order, only 4 LSB count
// print_string("\nPort-Mask: "); print_short(entry.pmask); write_char('\n');
} else if (IGMP_I->igmp_rtype == 0x3){ // Leave group
} else { // Leave group
if (sfr_data[2] & 0x10) {
print_string("\nIGMP_Entry FOUND\n");
reg_read_m(RTL837x_L2_DATA_OUT_B);
@@ -316,7 +343,7 @@ void igmp_packet_handler(void) __banked
// print_string("\nPort-Mask: "); print_short(entry.pmask); write_char('\n');
} else {
print_string("IGMP Entry already deleted\n");
return;
return 1;
}
if (!entry.pmask && idx) { // No more ports in that group and an actual entry?
// Delete Entry
@@ -328,14 +355,12 @@ void igmp_packet_handler(void) __banked
reg_read_m(RTL837X_TBL_CTRL);
} while (sfr_data[3] & 0x1);
print_string("IGMP Entry deleted\n");
return;
return 1;
}
} else { // Unknown message: ignore.
return;
}
if (!entry.pmask)
return;
return 1;
print_string("Updating IGMP entry\n");
// Write the updated entry
#ifdef IPMC_USES_L3MC
@@ -372,4 +397,5 @@ void igmp_packet_handler(void) __banked
reg_read_m(RTL837x_TBL_DATA_0);
print_sfr_data();
#endif
return 1;
}
+9 -1
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@@ -3,10 +3,18 @@
#include <stdint.h>
#define IGMP_PROTO 2
#define IGMP_V1_REPORT 0x12
#define IGMP_V2_REPORT 0x16
#define IGMP_V2_LEAVE 0x17
#define IGMP_V3_REPORT 0x22
#define IGMP_V3_TO_INCLUDE 3
#define IGMP_V3_TO_EXCLUDE 4
void igmp_setup(void) __banked;
void igmp_enable(void) __banked;
void igmp_router_port_set(uint16_t pmask) __banked;
void igmp_packet_handler(void) __banked;
uint8_t igmp_packet_handler(void) __banked;
void igmp_show(void) __banked;
#endif
+1 -2
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@@ -1052,8 +1052,7 @@ void handle_rx(void)
tcpip_output();
}
} else if (igmpEnabled && uip_buf[0] == 0x01 && uip_buf[1] == 0x00 && uip_buf[2] == 0x5e // IPv4-MC packet?
&& uip_buf[3] == 0x00 && uip_buf[4] == 0x00 && uip_buf[5] == 0x16) {
igmp_packet_handler();
&& igmp_packet_handler()) {
if (uip_len) {
tcpip_output();
}