114 lines
3.0 KiB
Diff
114 lines
3.0 KiB
Diff
From 65af96e0907ba9367aab9c1534b11c7f674c1e6a Mon Sep 17 00:00:00 2001
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From: Vladimir Oltean <vladimir.oltean@nxp.com>
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Date: Tue, 19 Apr 2022 13:29:07 +0300
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Subject: [PATCH 2/6] mreceive: join IGMP group by interface
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mreceive uses the old-style struct ip_mreq for IP_ADD_MEMBERSHIP, which
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takes the source address of the interface wishing to join.
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Since the IPV6_ADD_MEMBERSHIP variant only takes a struct ipv6_mreq
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which contains the ifindex and not the source address, we need to add
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support for that.
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In preparation for IPv6 support, add logic to join an IGMP group either
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by source address or by interface name, whichever is specified.
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Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
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---
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mreceive.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++-----
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1 file changed, 46 insertions(+), 5 deletions(-)
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--- a/mreceive.c
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+++ b/mreceive.c
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@@ -23,6 +23,7 @@
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#include <string.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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+#include <net/if.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <sys/time.h>
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@@ -61,7 +62,7 @@ Usage: mreceive [-g GROUP] [-p PORT] [-i
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-h Print the command usage.\n\n", VERSION);
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}
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-static void igmp_join(int s, in_addr_t multiaddr, in_addr_t interface)
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+static void igmp_join_by_saddr(int s, in_addr_t multiaddr, in_addr_t interface)
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{
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struct ip_mreq mreq;
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int ret;
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@@ -77,10 +78,34 @@ static void igmp_join(int s, in_addr_t m
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}
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}
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+static void igmp_join_by_if_name(int s, in_addr_t multicast,
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+ const char *if_name)
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+{
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+ struct ip_mreqn mreq = {};
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+ int if_index;
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+ int ret;
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+
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+ if_index = if_nametoindex(if_name);
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+ if (!if_index) {
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+ perror("if_nametoindex");
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+ exit(1);
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+ }
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+
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+ mreq.imr_multiaddr.s_addr = multicast;
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+ mreq.imr_ifindex = if_index;
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+
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+ ret = setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
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+ if (ret) {
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+ perror("setsockopt() IP_ADD_MEMBERSHIP");
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+ exit(1);
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+ }
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+}
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+
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int main(int argc, char *argv[])
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{
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struct sockaddr_in stLocal, stFrom;
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unsigned char achIn[BUFSIZE];
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+ const char *if_name;
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int s, i;
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int iTmp, iRet;
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int ipnum = 0;
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@@ -131,6 +156,17 @@ int main(int argc, char *argv[])
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ii++;
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ipnum++;
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}
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+ } else if (strcmp(argv[ii], "-I") == 0) {
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+ ii++;
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+ if (ii < argc) {
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+ if (if_name) {
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+ printf("Single interface expected\n");
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+ exit(1);
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+ }
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+
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+ if_name = argv[ii];
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+ ii++;
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+ }
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} else if (strcmp(argv[ii], "-n") == 0) {
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ii++;
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NUM = 1;
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@@ -167,11 +203,16 @@ int main(int argc, char *argv[])
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}
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/* join the multicast group. */
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- if (!ipnum) { /* single interface */
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- igmp_join(s, inet_addr(TEST_ADDR), INADDR_ANY);
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+ if (if_name) {
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+ igmp_join_by_if_name(s, inet_addr(TEST_ADDR), if_name);
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} else {
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- for (i = 0; i < ipnum; i++) {
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- igmp_join(s, inet_addr(TEST_ADDR), IP[i]);
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+ if (!ipnum) { /* single interface */
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+ igmp_join_by_saddr(s, inet_addr(TEST_ADDR), INADDR_ANY);
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+ } else {
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+ for (i = 0; i < ipnum; i++) {
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+ igmp_join_by_saddr(s, inet_addr(TEST_ADDR),
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+ IP[i]);
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+ }
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}
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}
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