Ensure signal-safety of signal handlers

[odhcp6c.git] / src / ra.c

diff --git a/src/ra.c b/src/ra.c
index 6132e455189b1ce0b527b0322c97166c42f600a9..9c5eb220897552b629e66df8fb5bb3d7eda2ff6a 100644 (file)
--- a/src/ra.c
+++ b/src/ra.c
@@ -55,6 +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)
@@ -92,6 +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;
@@ -132,9 +142,16 @@ int ra_init(const char *ifname, const struct in6_addr *ifid)
 
 static void ra_send_rs(int signal __attribute__((unused)))
 {
-       const struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
        const struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, if_index};
-       sendto(sock, &rs, sizeof(rs), MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest));
+       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);
+
+       sendto(sock, &rs, len, MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest));
 
        if (++rs_attempt <= 3)
                alarm(4);
@@ -179,6 +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;
@@ -311,11 +336,13 @@ bool ra_process(void)
                        update_proc("conf", "hop_limit", adv->nd_ra_curhoplimit);
 
                // Parse ND parameters
-               if (ntohl(adv->nd_ra_reachable) <= 3600000)
-                       update_proc("neigh", "base_reachable_time_ms", ntohl(adv->nd_ra_reachable));
+               uint32_t reachable = ntohl(adv->nd_ra_reachable);
+               if (reachable > 0 && reachable <= 3600000)
+                       update_proc("neigh", "base_reachable_time_ms", reachable);
 
-               if (ntohl(adv->nd_ra_retransmit) <= 60000)
-                       update_proc("neigh", "retrans_time_ms", ntohl(adv->nd_ra_retransmit));
+               uint32_t retransmit = ntohl(adv->nd_ra_retransmit);
+               if (retransmit > 0 && retransmit <= 60000)
+                       update_proc("neigh", "retrans_time_ms", retransmit);
 
 
                // Evaluate options
@@ -356,18 +383,16 @@ bool ra_process(void)
                                                || entry.valid < entry.preferred)
                                        continue;
 
+                               if (pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_ONLINK)
+                                       changed |= odhcp6c_update_entry_safe(STATE_RA_ROUTE, &entry, 7200);
+
                                if (!(pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_AUTO) ||
-                                               pinfo->nd_opt_pi_prefix_len != 64) {
-                                       if (pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_ONLINK)
-                                               changed |= odhcp6c_update_entry_safe(STATE_RA_ROUTE, &entry, 7200);
+                                               pinfo->nd_opt_pi_prefix_len != 64)
                                        continue;
-                               }
 
                                entry.target.s6_addr32[2] = lladdr.s6_addr32[2];
                                entry.target.s6_addr32[3] = lladdr.s6_addr32[3];
 
-                               if (!(pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_ONLINK))
-                                       entry.length = 128;
                                changed |= odhcp6c_update_entry_safe(STATE_RA_PREFIX, &entry, 7200);
                        } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 2) {
                                entry.router = from.sin6_addr;