--- /dev/null
+From fed8c3db10bc9d3a1e799a774924c00522595d0c Mon Sep 17 00:00:00 2001
+From: Evgeny Yurchenko <evg.yurch@rogers.com>
+Date: Mon, 4 Jan 2010 05:13:59 +0500
+Subject: [PATCH] Send IGMP packets with IP Router Alert option [RFC 2113] included in IP header
+
+---
+ src/igmp.c | 17 ++++++++++++-----
+ src/igmpproxy.h | 1 +
+ 2 files changed, 13 insertions(+), 5 deletions(-)
+
+diff --git a/src/igmp.c b/src/igmp.c
+index a0cd27d..b547688 100644
+--- a/src/igmp.c
++++ b/src/igmp.c
+@@ -67,7 +67,7 @@ void initIgmp() {
+ * - Checksum (let the kernel fill it in)
+ */
+ ip->ip_v = IPVERSION;
+- ip->ip_hl = sizeof(struct ip) >> 2;
++ ip->ip_hl = (sizeof(struct ip) + 4) >> 2; /* +4 for Router Alert option */
+ ip->ip_tos = 0xc0; /* Internet Control */
+ ip->ip_ttl = MAXTTL; /* applies to unicasts only */
+ ip->ip_p = IPPROTO_IGMP;
+@@ -213,7 +213,7 @@ void buildIgmp(uint32_t src, uint32_t dst, int type, int code, uint32_t group, i
+ ip = (struct ip *)send_buf;
+ ip->ip_src.s_addr = src;
+ ip->ip_dst.s_addr = dst;
+- ip_set_len(ip, MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen);
++ ip_set_len(ip, IP_HEADER_RAOPT_LEN + IGMP_MINLEN + datalen);
+
+ if (IN_MULTICAST(ntohl(dst))) {
+ ip->ip_ttl = curttl;
+@@ -221,13 +221,20 @@ void buildIgmp(uint32_t src, uint32_t dst, int type, int code, uint32_t group, i
+ ip->ip_ttl = MAXTTL;
+ }
+
+- igmp = (struct igmp *)(send_buf + MIN_IP_HEADER_LEN);
++ /* Add Router Alert option */
++ ((u_char*)send_buf+MIN_IP_HEADER_LEN)[0] = IPOPT_RA;
++ ((u_char*)send_buf+MIN_IP_HEADER_LEN)[1] = 0x04;
++ ((u_char*)send_buf+MIN_IP_HEADER_LEN)[2] = 0x00;
++ ((u_char*)send_buf+MIN_IP_HEADER_LEN)[3] = 0x00;
++
++ igmp = (struct igmp *)(send_buf + IP_HEADER_RAOPT_LEN);
+ igmp->igmp_type = type;
+ igmp->igmp_code = code;
+ igmp->igmp_group.s_addr = group;
+ igmp->igmp_cksum = 0;
+ igmp->igmp_cksum = inetChksum((u_short *)igmp,
+- IGMP_MINLEN + datalen);
++ IP_HEADER_RAOPT_LEN + datalen);
++
+ }
+
+ /*
+@@ -257,7 +264,7 @@ void sendIgmp(uint32_t src, uint32_t dst, int type, int code, uint32_t group, in
+ #endif
+ sdst.sin_addr.s_addr = dst;
+ if (sendto(MRouterFD, send_buf,
+- MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen, 0,
++ IP_HEADER_RAOPT_LEN + IGMP_MINLEN + datalen, 0,
+ (struct sockaddr *)&sdst, sizeof(sdst)) < 0) {
+ if (errno == ENETDOWN)
+ my_log(LOG_ERR, errno, "Sender VIF was down.");
+diff --git a/src/igmpproxy.h b/src/igmpproxy.h
+index 0de7791..4df8a79 100644
+--- a/src/igmpproxy.h
++++ b/src/igmpproxy.h
+@@ -64,6 +64,7 @@
+ #define MAX_IP_PACKET_LEN 576
+ #define MIN_IP_HEADER_LEN 20
+ #define MAX_IP_HEADER_LEN 60
++#define IP_HEADER_RAOPT_LEN 24
+
+ #define MAX_MC_VIFS 32 // !!! check this const in the specific includes
+
+--
+1.7.2.5
+