mirror of https://github.com/hak5/openwrt.git
80 lines
3.0 KiB
Diff
80 lines
3.0 KiB
Diff
From fed8c3db10bc9d3a1e799a774924c00522595d0c Mon Sep 17 00:00:00 2001
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From: Evgeny Yurchenko <evg.yurch@rogers.com>
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Date: Mon, 4 Jan 2010 05:13:59 +0500
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Subject: [PATCH] Send IGMP packets with IP Router Alert option [RFC 2113] included in IP header
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---
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src/igmp.c | 17 ++++++++++++-----
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src/igmpproxy.h | 1 +
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2 files changed, 13 insertions(+), 5 deletions(-)
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diff --git a/src/igmp.c b/src/igmp.c
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index a0cd27d..b547688 100644
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--- a/src/igmp.c
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+++ b/src/igmp.c
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@@ -67,7 +67,7 @@ void initIgmp() {
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* - Checksum (let the kernel fill it in)
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*/
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ip->ip_v = IPVERSION;
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- ip->ip_hl = sizeof(struct ip) >> 2;
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+ ip->ip_hl = (sizeof(struct ip) + 4) >> 2; /* +4 for Router Alert option */
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ip->ip_tos = 0xc0; /* Internet Control */
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ip->ip_ttl = MAXTTL; /* applies to unicasts only */
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ip->ip_p = IPPROTO_IGMP;
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@@ -213,7 +213,7 @@ void buildIgmp(uint32_t src, uint32_t dst, int type, int code, uint32_t group, i
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ip = (struct ip *)send_buf;
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ip->ip_src.s_addr = src;
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ip->ip_dst.s_addr = dst;
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- ip_set_len(ip, MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen);
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+ ip_set_len(ip, IP_HEADER_RAOPT_LEN + IGMP_MINLEN + datalen);
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if (IN_MULTICAST(ntohl(dst))) {
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ip->ip_ttl = curttl;
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@@ -221,13 +221,20 @@ void buildIgmp(uint32_t src, uint32_t dst, int type, int code, uint32_t group, i
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ip->ip_ttl = MAXTTL;
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}
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- igmp = (struct igmp *)(send_buf + MIN_IP_HEADER_LEN);
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+ /* Add Router Alert option */
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+ ((u_char*)send_buf+MIN_IP_HEADER_LEN)[0] = IPOPT_RA;
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+ ((u_char*)send_buf+MIN_IP_HEADER_LEN)[1] = 0x04;
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+ ((u_char*)send_buf+MIN_IP_HEADER_LEN)[2] = 0x00;
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+ ((u_char*)send_buf+MIN_IP_HEADER_LEN)[3] = 0x00;
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+
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+ igmp = (struct igmp *)(send_buf + IP_HEADER_RAOPT_LEN);
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igmp->igmp_type = type;
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igmp->igmp_code = code;
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igmp->igmp_group.s_addr = group;
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igmp->igmp_cksum = 0;
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igmp->igmp_cksum = inetChksum((u_short *)igmp,
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- IGMP_MINLEN + datalen);
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+ IP_HEADER_RAOPT_LEN + datalen);
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+
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}
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/*
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@@ -257,7 +264,7 @@ void sendIgmp(uint32_t src, uint32_t dst, int type, int code, uint32_t group, in
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#endif
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sdst.sin_addr.s_addr = dst;
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if (sendto(MRouterFD, send_buf,
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- MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen, 0,
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+ IP_HEADER_RAOPT_LEN + IGMP_MINLEN + datalen, 0,
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(struct sockaddr *)&sdst, sizeof(sdst)) < 0) {
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if (errno == ENETDOWN)
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my_log(LOG_ERR, errno, "Sender VIF was down.");
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diff --git a/src/igmpproxy.h b/src/igmpproxy.h
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index 0de7791..4df8a79 100644
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--- a/src/igmpproxy.h
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+++ b/src/igmpproxy.h
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@@ -64,6 +64,7 @@
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#define MAX_IP_PACKET_LEN 576
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#define MIN_IP_HEADER_LEN 20
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#define MAX_IP_HEADER_LEN 60
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+#define IP_HEADER_RAOPT_LEN 24
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#define MAX_MC_VIFS 32 // !!! check this const in the specific includes
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--
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1.7.2.5
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