make the code work for bridge interfaces

[project/mdnsd.git] / dns.c

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);