X-Git-Url: https://git.archive.openwrt.org/?a=blobdiff_plain;f=dns.c;h=5390fe6216097920b9ee08ad59b197950d1dcb8f;hb=6a432a41b9629b6e70a41308f6d9487acf6f4621;hp=1d8a8308b8c87dda426107f61bb21269ebf9ac54;hpb=788316ef66136e6a68d881e5b24ccf5a98fa4550;p=project%2Fmdnsd.git diff --git a/dns.c b/dns.c index 1d8a830..5390fe6 100644 --- a/dns.c +++ b/dns.c @@ -30,13 +30,14 @@ #include #include +#include #include "announce.h" #include "util.h" #include "dns.h" -char *rdata_buffer; -static char *name_buffer; +char rdata_buffer[MAX_DATA_LEN + 1]; +static char name_buffer[MAX_NAME_LEN + 1]; const char* dns_type_string(uint16_t type) @@ -64,44 +65,73 @@ dns_type_string(uint16_t type) return "N/A"; } -void -dns_send_question(struct uloop_fd *u, char *question, int type) +static int +dns_send_packet(int fd, struct iovec *iov, int iov_len) { - 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 }; - int len; + static size_t cmsg_data[( CMSG_SPACE(sizeof(struct in_pktinfo)) / sizeof(size_t)) + 1]; + static struct sockaddr_in a = { + .sin_family = AF_INET, + .sin_port = htons(MCAST_PORT), + }; + static struct msghdr m = { + .msg_name = (struct sockaddr *) &a, + .msg_namelen = sizeof(a), + .msg_control = cmsg_data, + .msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)), + }; + struct in_pktinfo *pkti; + struct cmsghdr *cmsg; + + m.msg_iov = iov; + m.msg_iovlen = iov_len; + + memset(cmsg_data, 0, sizeof(cmsg_data)); + cmsg = CMSG_FIRSTHDR(&m); + cmsg->cmsg_len = m.msg_controllen; + cmsg->cmsg_level = IPPROTO_IP; + cmsg->cmsg_type = IP_PKTINFO; + + pkti = (struct in_pktinfo*) CMSG_DATA(cmsg); + pkti->ipi_ifindex = iface_index; - a.sin_family = AF_INET; a.sin_addr.s_addr = inet_addr(MCAST_ADDR); - a.sin_port = htons(MCAST_PORT); - h.questions = __cpu_to_be16(1); + return sendmsg(fd, &m, 0); +} + +void +dns_send_question(struct uloop_fd *u, const char *question, int type) +{ + static struct dns_header h = { + .questions = cpu_to_be16(1), + }; + static struct dns_question q = { + .class = cpu_to_be16(1), + }; + static struct iovec iov[] = { + { + .iov_base = &h, + .iov_len = sizeof(h), + }, + { + .iov_base = name_buffer, + }, + { + .iov_base = &q, + .iov_len = sizeof(q), + } + }; + int len; + q.type = __cpu_to_be16(type); - q.class = __cpu_to_be16(1); - len = dn_comp(question, buffer, MAX_NAME_LEN, NULL, NULL); + len = dn_comp(question, (void *) name_buffer, sizeof(name_buffer), NULL, NULL); if (len < 1) return; - m.msg_name = &a; - m.msg_namelen = sizeof(struct sockaddr_in); - m.msg_iov = iov; - m.msg_iovlen = 3; - - iov[0].iov_base = &h; - iov[0].iov_len = sizeof(struct dns_header); - - iov[1].iov_base = buffer; iov[1].iov_len = len; - iov[2].iov_base = &q; - iov[2].iov_len = sizeof(struct dns_question); - - if (sendmsg(u->fd, &m, 0) < 0) + if (dns_send_packet(u->fd, iov, ARRAY_SIZE(iov)) < 0) fprintf(stderr, "failed to send question\n"); else DBG(1, "Q <- %s %s\n", dns_type_string(type), question); @@ -127,7 +157,7 @@ dns_init_answer(void) } void -dns_add_answer(int type, uint8_t *rdata, uint16_t rdlength) +dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength) { struct dns_reply *a = &dns_reply[dns_answer_cnt]; if (dns_answer_cnt == MAX_ANSWER) @@ -139,34 +169,20 @@ dns_add_answer(int type, uint8_t *rdata, uint16_t rdlength) } void -dns_send_answer(struct uloop_fd *u, char *answer) +dns_send_answer(struct uloop_fd *u, const char *answer) { uint8_t buffer[256]; struct dns_header h = { 0 }; - struct msghdr m = { 0 }; struct iovec *iov; - struct sockaddr_in in = { 0 }; int len, i; if (!dns_answer_cnt) return; - in.sin_family = AF_INET; - in.sin_addr.s_addr = inet_addr(MCAST_ADDR); - in.sin_port = htons(MCAST_PORT); - h.answers = __cpu_to_be16(dns_answer_cnt); h.flags = __cpu_to_be16(0x8400); - iov = malloc(sizeof(struct iovec) * ((dns_answer_cnt * 3) + 1)); - if (!iov) - return; - - m.msg_name = ∈ - m.msg_namelen = sizeof(struct sockaddr_in); - m.msg_iov = iov; - m.msg_iovlen = (dns_answer_cnt * 3) + 1; - + iov = alloca(sizeof(struct iovec) * ((dns_answer_cnt * 3) + 1)); iov[0].iov_base = &h; iov[0].iov_len = sizeof(struct dns_header); @@ -196,7 +212,7 @@ dns_send_answer(struct uloop_fd *u, char *answer) DBG(1, "A <- %s %s\n", dns_type_string(dns_reply[i].type), answer); } - if (sendmsg(u->fd, &m, 0) < 0) + if (dns_send_packet(u->fd, iov, (dns_answer_cnt * 3) + 1) < 0) fprintf(stderr, "failed to send question\n"); for (i = 0; i < dns_answer_cnt; i++) { @@ -207,7 +223,7 @@ dns_send_answer(struct uloop_fd *u, char *answer) } static int -scan_name(uint8_t *buffer, int len) +scan_name(const uint8_t *buffer, int len) { int offset = 0; @@ -290,7 +306,7 @@ dns_consume_answer(uint8_t **data, int *len) } char* -dns_consume_name(uint8_t *base, int blen, uint8_t **data, int *len) +dns_consume_name(const uint8_t *base, int blen, uint8_t **data, int *len) { int nlen = scan_name(*data, *len); @@ -307,25 +323,3 @@ dns_consume_name(uint8_t *base, int blen, uint8_t **data, int *len) return name_buffer; } - -int -dns_init(void) -{ - name_buffer = malloc(MAX_NAME_LEN + 1); - rdata_buffer = malloc(MAX_DATA_LEN + 1); - - if (!name_buffer || !rdata_buffer) - return -1; - - memset(name_buffer, 0, MAX_NAME_LEN + 1); - memset(rdata_buffer, 0, MAX_NAME_LEN + 1); - - return 0; -} - -void -dns_cleanup(void) -{ - free(name_buffer); - free(rdata_buffer); -}