From be05c0ded0257cbb82857f6d01226ef6de28befe Mon Sep 17 00:00:00 2001
From: Steven Barth <steven@midlink.org>
Date: Mon, 11 Nov 2013 15:34:05 +0100
Subject: [PATCH 1/1] Finalizing bfd work

---
 src/bfd.c     | 35 ++++-------------------------------
 src/odhcp6c.c | 18 ++++++++++++++++--
 2 files changed, 20 insertions(+), 33 deletions(-)

diff --git a/src/bfd.c b/src/bfd.c
index 11fade1..1822555 100644
--- a/src/bfd.c
+++ b/src/bfd.c
@@ -12,6 +12,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/filter.h>
 
+#include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
 
@@ -86,8 +87,10 @@ static void bfd_send(int signal __attribute__((unused)))
 		do {
 			ssize_t read = recv(rtnl, buf, sizeof(buf), 0);
 			nhm = (struct nlmsghdr*)buf;
-			if (read < 0 || !NLMSG_OK(nhm, (size_t)read))
+			if ((read < 0 && errno == EINTR) || !NLMSG_OK(nhm, (size_t)read))
 				continue;
+			else if (read < 0)
+				break;
 
 			for (; read > 0 && NLMSG_OK(nhm, (size_t)read); nhm = NLMSG_NEXT(nhm, read)) {
 				ssize_t attrlen = NLMSG_PAYLOAD(nhm, sizeof(struct ndmsg));
@@ -120,17 +123,6 @@ static void bfd_send(int signal __attribute__((unused)))
 	ping.ip6.ip6_src = cpd->target;
 	ping.ip6.ip6_dst = cpd->target;
 
-/*
-	uint16_t sum = cksum(&ping.ip6.ip6_src, sizeof(ping.ip6.ip6_src), 0);
-	sum = cksum(&ping.ip6.ip6_dst, sizeof(ping.ip6.ip6_dst), ~sum);
-	sum = cksum(&ping.ip6.ip6_plen, sizeof(ping.ip6.ip6_plen), ~sum);
-
-	uint8_t next[4] = {0, 0, 0, ping.ip6.ip6_nxt};
-	sum = cksum(next, sizeof(next), ~sum);
-
-	ping.icmp6.icmp6_cksum = cksum(&ping.icmp6, sizeof(ping.icmp6), ~sum);
-*/
-
 	struct sock_filter bpf[] = {
 		BPF_STMT(BPF_LD | BPF_W | BPF_ABS, offsetof(struct ip6_hdr, ip6_plen)),
 		BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 8 << 16 | IPPROTO_ICMPV6 << 8 | 254, 0, 13),
@@ -217,22 +209,3 @@ void bfd_stop(void)
 	sock = -1;
 	rtnl = -1;
 }
-
-/*
-
-uint16_t cksum(const uint16_t *addr, size_t count, uint16_t start)
-{
-	uint32_t sum = start;
-
-	while (count > 1) {
-		sum += *addr++;
-		count -= 2;
-	}
-
-	while (sum >> 16)
-		sum = (sum & 0xffff) + (sum >> 16);
-
-	return ~sum;
-}
-
-*/
diff --git a/src/odhcp6c.c b/src/odhcp6c.c
index 2c5bfad..de03b81 100644
--- a/src/odhcp6c.c
+++ b/src/odhcp6c.c
@@ -63,10 +63,14 @@ int main(_unused int argc, char* const argv[])
 	static struct in6_addr ifid = IN6ADDR_ANY_INIT;
 	int sol_timeout = 120;
 
+#ifdef EXT_BFD_PING
+	int bfd_interval = 0, bfd_loss = 3;
+#endif
+
 	bool help = false, daemonize = false;
 	int logopt = LOG_PID;
 	int c, request_pd = 0;
-	while ((c = getopt(argc, argv, "S::N:P:Fc:i:r:s:kt:hedp:")) != -1) {
+	while ((c = getopt(argc, argv, "S::N:P:FB:c:i:r:s:kt:hedp:")) != -1) {
 		switch (c) {
 		case 'S':
 			allow_slaac_only = (optarg) ? atoi(optarg) : -1;
@@ -100,6 +104,12 @@ int main(_unused int argc, char* const argv[])
 			ia_pd_mode = IA_MODE_FORCE;
 			break;
 
+#ifdef EXT_BFD_PING
+		case 'B':
+			bfd_interval = atoi(optarg);
+			break;
+#endif
+
 		case 'c':
 			l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
 			if (l > 0) {
@@ -267,7 +277,8 @@ int main(_unused int argc, char* const argv[])
 		bound = true;
 		syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 #ifdef EXT_BFD_PING
-		bfd_start(ifname, 3, 10);
+		if (bfd_interval > 0)
+			bfd_start(ifname, bfd_loss, bfd_interval);
 #endif
 
 		while (do_signal == 0 || do_signal == SIGUSR1) {
@@ -353,6 +364,9 @@ static int usage(void)
 	"	-N <mode>	Mode for requesting addresses [try|force|none]\n"
 	"	-P <length>	Request IPv6-Prefix (0 = auto)\n"
 	"	-F		Force IPv6-Prefix\n"
+#ifdef EXT_BFD_PING
+	"	-B <interval>	Enable BFD ping check\n"
+#endif
 	"	-c <clientid>	Override client-ID (base-16 encoded)\n"
 	"	-i <iface-id>	Use a custom interface identifier for RA handling\n"
 	"	-r <options>	Options to be requested (comma-separated)\n"
-- 
2.39.2