Ensure signal-safety of signal handlers

1 files changed, 23 insertions, 16 deletions

diff --git a/src/ra.c b/src/ra.c
index baaee9b..9c5eb22 100644
--- a/src/ra.c
+++ b/src/ra.c
@@ -26,7 +26,6 @@
 #include <arpa/inet.h>
 #include <sys/socket.h>
 #include <sys/types.h>
-#include <sys/ioctl.h>
 #include <netinet/in.h>
 #include <netinet/icmp6.h>
 
@@ -56,6 +55,15 @@ static char if_name[IF_NAMESIZE] = {0};
 static volatile int rs_attempt = 0;
 static struct in6_addr lladdr = IN6ADDR_ANY_INIT;
 
+struct {
+	struct icmp6_hdr hdr;
+	struct icmpv6_opt lladdr;
+} rs = {
+	.hdr = {ND_ROUTER_SOLICIT, 0, 0, {{0}}},
+	.lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
+};
+
+
 static void ra_send_rs(int signal __attribute__((unused)));
 
 int ra_init(const char *ifname, const struct in6_addr *ifid)
@@ -93,6 +101,7 @@ int ra_init(const char *ifname, const struct in6_addr *ifid)
 		.ifi = {.ifi_index = if_index}
 	};
 	send(rtnl, &req, sizeof(req), 0);
+	ra_link_up();
 
 	// Filter ICMPv6 package types
 	struct icmp6_filter filt;
@@ -133,22 +142,12 @@ int ra_init(const char *ifname, const struct in6_addr *ifid)
 
 static void ra_send_rs(int signal __attribute__((unused)))
 {
-	struct {
-		struct icmp6_hdr hdr;
-		struct icmpv6_opt lladdr;
-	} rs = {
-		.hdr = {ND_ROUTER_SOLICIT, 0, 0, {{0}}},
-		.lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
-	};
 	const struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, if_index};
-	size_t len = sizeof(rs);
-
-	struct ifreq ifr;
-	memset(&ifr, 0, sizeof(ifr));
-	strncpy(ifr.ifr_name, if_name, sizeof(ifr.ifr_name));
-	if ((rs_attempt % 2 == 0) && !ioctl(sock, SIOCGIFHWADDR, &ifr)
-			&& memcmp(rs.lladdr.data, ifr.ifr_hwaddr.sa_data, 6))
-		memcpy(rs.lladdr.data, ifr.ifr_hwaddr.sa_data, 6);
+	const struct icmpv6_opt llnull = {ND_OPT_SOURCE_LINKADDR, 1, {0}};
+	size_t len;
+
+	if ((rs_attempt % 2 == 0) && memcmp(&rs.lladdr, &llnull, sizeof(llnull)))
+		len = sizeof(rs);
 	else
 		len = sizeof(struct icmp6_hdr);
 
@@ -197,6 +196,14 @@ bool ra_link_up(void)
 				resp.msg.ifi_index != if_index)
 			continue;
 
+		ssize_t alen = NLMSG_PAYLOAD(&resp.hdr, sizeof(resp.msg));
+		for (struct rtattr *rta = (struct rtattr*)(resp.pad);
+				RTA_OK(rta, alen); rta = RTA_NEXT(rta, alen)) {
+			if (rta->rta_type == IFLA_ADDRESS &&
+					RTA_PAYLOAD(rta) >= sizeof(rs.lladdr.data))
+				memcpy(rs.lladdr.data, RTA_DATA(rta), sizeof(rs.lladdr.data));
+		}
+
 		bool hascarrier = resp.msg.ifi_flags & IFF_LOWER_UP;
 		if (!firstcall && nocarrier != !hascarrier)
 			ret = true;