src/patches/igmpproxy-001-Send-IGMP-packets-with-IP-Router-Alert-option-RFC-21.patch

   1 From fed8c3db10bc9d3a1e799a774924c00522595d0c Mon Sep 17 00:00:00 2001
   2 From: Evgeny Yurchenko <evg.yurch@rogers.com>
   3 Date: Mon, 4 Jan 2010 05:13:59 +0500
   4 Subject: [PATCH] Send IGMP packets with IP Router Alert option [RFC 2113] included in IP header
   5
   6 ---
   7  src/igmp.c      |   17 ++++++++++++-----
   8  src/igmpproxy.h |    1 +
   9  2 files changed, 13 insertions(+), 5 deletions(-)
  10
  11 diff --git a/src/igmp.c b/src/igmp.c
  12 index a0cd27d..b547688 100644
  13 --- a/src/igmp.c
  14 +++ b/src/igmp.c
  15 @@ -67,7 +67,7 @@ void initIgmp() {
  16       * - Checksum (let the kernel fill it in)
  17       */
  18      ip->ip_v   = IPVERSION;
  19 -    ip->ip_hl  = sizeof(struct ip) >> 2;
  20 +    ip->ip_hl  = (sizeof(struct ip) + 4) >> 2; /* +4 for Router Alert option */
  21      ip->ip_tos = 0xc0;      /* Internet Control */
  22      ip->ip_ttl = MAXTTL;    /* applies to unicasts only */
  23      ip->ip_p   = IPPROTO_IGMP;
  24 @@ -213,7 +213,7 @@ void buildIgmp(uint32_t src, uint32_t dst, int type, int code, uint32_t group, i
  25      ip                      = (struct ip *)send_buf;
  26      ip->ip_src.s_addr       = src;
  27      ip->ip_dst.s_addr       = dst;
  28 -    ip_set_len(ip, MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen);
  29 +    ip_set_len(ip, IP_HEADER_RAOPT_LEN + IGMP_MINLEN + datalen);
  30
  31      if (IN_MULTICAST(ntohl(dst))) {
  32          ip->ip_ttl = curttl;
  33 @@ -221,13 +221,20 @@ void buildIgmp(uint32_t src, uint32_t dst, int type, int code, uint32_t group, i
  34          ip->ip_ttl = MAXTTL;
  35      }
  36
  37 -    igmp                    = (struct igmp *)(send_buf + MIN_IP_HEADER_LEN);
  38 +    /* Add Router Alert option */
  39 +    ((u_char*)send_buf+MIN_IP_HEADER_LEN)[0] = IPOPT_RA;
  40 +    ((u_char*)send_buf+MIN_IP_HEADER_LEN)[1] = 0x04;
  41 +    ((u_char*)send_buf+MIN_IP_HEADER_LEN)[2] = 0x00;
  42 +    ((u_char*)send_buf+MIN_IP_HEADER_LEN)[3] = 0x00;
  43 +
  44 +    igmp                    = (struct igmp *)(send_buf + IP_HEADER_RAOPT_LEN);
  45      igmp->igmp_type         = type;
  46      igmp->igmp_code         = code;
  47      igmp->igmp_group.s_addr = group;
  48      igmp->igmp_cksum        = 0;
  49      igmp->igmp_cksum        = inetChksum((u_short *)igmp,
  50 -                                         IGMP_MINLEN + datalen);
  51 +                                         IP_HEADER_RAOPT_LEN + datalen);
  52 +
  53  }
  54
  55  /*
  56 @@ -257,7 +264,7 @@ void sendIgmp(uint32_t src, uint32_t dst, int type, int code, uint32_t group, in
  57  #endif
  58      sdst.sin_addr.s_addr = dst;
  59      if (sendto(MRouterFD, send_buf,
  60 -               MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen, 0,
  61 +               IP_HEADER_RAOPT_LEN + IGMP_MINLEN + datalen, 0,
  62                 (struct sockaddr *)&sdst, sizeof(sdst)) < 0) {
  63          if (errno == ENETDOWN)
  64              my_log(LOG_ERR, errno, "Sender VIF was down.");
  65 diff --git a/src/igmpproxy.h b/src/igmpproxy.h
  66 index 0de7791..4df8a79 100644
  67 --- a/src/igmpproxy.h
  68 +++ b/src/igmpproxy.h
  69 @@ -64,6 +64,7 @@
  70  #define MAX_IP_PACKET_LEN      576
  71  #define MIN_IP_HEADER_LEN      20
  72  #define MAX_IP_HEADER_LEN      60
  73 +#define IP_HEADER_RAOPT_LEN    24
  74
  75  #define MAX_MC_VIFS    32     // !!! check this const in the specific includes
  76
  77 --
  78 1.7.2.5
  79