make the code work for bridge interfaces

Signed-off-by: John Crispin <blogic@openwrt.org>

diff --git a/dns.c b/dns.c
index 1d8a830..ecfaa63 100644 (file)
--- a/dns.c
+++ b/dns.c
@@ -67,12 +67,16 @@ dns_type_string(uint16_t type)
 void
 dns_send_question(struct uloop_fd *u, char *question, int type)
 {
+       size_t cmsg_data[( CMSG_SPACE(sizeof(struct in_pktinfo)) / sizeof(size_t)) + 1];
        unsigned char buffer[MAX_NAME_LEN];
        struct dns_header h = { 0 };
        struct dns_question q = { 0 };
        struct msghdr m = { 0 };
        struct iovec iov[3] = { {0}, {0}, {0} };
        struct sockaddr_in a = { 0 };
+       struct in_pktinfo *pkti;
+       struct cmsghdr *cmsg;
+       struct in_addr in;
        int len;
 
        a.sin_family = AF_INET;
@@ -92,6 +96,20 @@ dns_send_question(struct uloop_fd *u, char *question, int type)
        m.msg_iov = iov;
        m.msg_iovlen = 3;
 
+       memset(cmsg_data, 0, sizeof(cmsg_data));
+       m.msg_control = cmsg_data;
+       m.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo));
+
+       cmsg = CMSG_FIRSTHDR(&m);
+       cmsg->cmsg_len = m.msg_controllen;
+       cmsg->cmsg_level = IPPROTO_IP;
+       cmsg->cmsg_type = IP_PKTINFO;
+
+       inet_aton(iface_ip, &in);
+
+       pkti = (struct in_pktinfo*) CMSG_DATA(cmsg);
+       pkti->ipi_ifindex = iface_index;
+
        iov[0].iov_base = &h;
        iov[0].iov_len = sizeof(struct dns_header);
 

diff --git a/main.c b/main.c
index a6c99b5..cc17903 100644 (file)
--- a/main.c
+++ b/main.c
@@ -42,6 +42,7 @@
 static struct uloop_timeout reconnect;
 char *iface_name = "eth0";
 const char *iface_ip;
+int iface_index;
 
 static int
 parse_answer(struct uloop_fd *u, uint8_t *buffer, int len, uint8_t **b, int *rlen, int cache)
@@ -185,7 +186,6 @@ reconnect_socket(struct uloop_timeout *timeout)
 
                uloop_fd_add(&listener, ULOOP_READ);
                sleep(5);
-               dns_send_question(&listener, "_services._dns-sd._tcp.local", TYPE_PTR);
                dns_send_question(&listener, "_services._dns-sd._udp.local", TYPE_PTR);
                announce_init(&listener);
        }
@@ -226,7 +226,15 @@ main(int argc, char **argv)
                fprintf(stderr, "failed to read ip for %s\n", iface_name);
                return -1;
        }
-       fprintf(stderr, "interface %s has ip %s\n", iface_name, iface_ip);
+
+       iface_index = get_iface_index(iface_name);
+
+       if (!iface_index) {
+               fprintf(stderr, "failed to read index for %s\n", iface_name);
+               return -1;
+       }
+
+       fprintf(stderr, "interface %s has ip %s and index %d\n", iface_name, iface_ip, iface_index);
        signal_setup();
 
        if (dns_init())

diff --git a/util.c b/util.c
index a4a117b..1708a40 100644 (file)
--- a/util.c
+++ b/util.c
@@ -98,6 +98,28 @@ get_iface_ipv4(const char *ifname)
        return ret;
 }
 
+int
+get_iface_index(const char *ifname)
+{
+       struct ifreq ir;
+       int sock;
+
+       sock = socket(AF_INET, SOCK_DGRAM, 0);
+       if (sock < 0)
+               return 0;
+
+       memset(&ir, 0, sizeof(struct ifreq));
+
+       strncpy(ir.ifr_name, ifname, sizeof(ir.ifr_name));
+
+       if (ioctl(sock, SIOCGIFINDEX, &ir) < 0)
+               return 0;
+
+       close(sock);
+
+       return ir.ifr_ifindex;
+}
+
 char*
 get_hostname(void)
 {
@@ -116,15 +138,19 @@ socket_setup(int fd, const char *ip)
        uint8_t ttl = 255;
        int yes = 1;
        int no = 0;
-       struct sockaddr_in sa;
+       struct sockaddr_in sa = { 0 };
+       struct in_addr in;
+
+       inet_aton(iface_ip, &in);
 
        sa.sin_family = AF_INET;
        sa.sin_port = htons(MCAST_PORT);
        inet_pton(AF_INET, MCAST_ADDR, &sa.sin_addr);
 
        memset(&mreq, 0, sizeof(mreq));
-       mreq.imr_address.s_addr = htonl(INADDR_ANY);
+       mreq.imr_address.s_addr = in.s_addr;
        mreq.imr_multiaddr = sa.sin_addr;
+       mreq.imr_ifindex = iface_index;
 
        if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
                fprintf(stderr, "ioctl failed: IP_MULTICAST_TTL\n");
@@ -132,6 +158,13 @@ socket_setup(int fd, const char *ip)
        if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0)
                fprintf(stderr, "ioctl failed: SO_REUSEADDR\n");
 
+       /* Some network drivers have issues with dropping membership of
+        * mcast groups when the iface is down, but don't allow rejoining
+        * when it comes back up. This is an ugly workaround
+        * -- this was copied from avahi --
+        */
+       setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq));
+
        if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) {
                fprintf(stderr, "failed to join multicast group: %s\n", strerror(errno));
                close(fd);

diff --git a/util.h b/util.h
index 6c73904..fe9f1ea 100644 (file)
--- a/util.h
+++ b/util.h
@@ -22,6 +22,7 @@
 extern int debug;
 extern struct uloop_fd listener;
 extern const char *iface_ip;
+extern int iface_index;
 
 void *memdup(void *d, int l);
 
@@ -29,6 +30,7 @@ extern void signal_setup(void);
 extern int socket_setup(int fd, const char *ip);
 extern char* get_hostname(void);
 extern const char* get_iface_ipv4(const char *ifname);
+extern int get_iface_index(const char *ifname);
 extern uint32_t rand_time_delta(uint32_t t);
 
 #endif