X-Git-Url: http://git.archive.openwrt.org/?p=project%2Fmdnsd.git;a=blobdiff_plain;f=dns.c;h=495177412fdbd2a38a1043ca2d61c29e4c16b145;hp=ecfaa6353131f646f42abd9220654147ed6e22fa;hb=2c1fe9afacc9379dcfd0db911fc9ee45adfdc0f4;hpb=8381f595a6066f893cc24e8a161e27a10a140cf0 diff --git a/dns.c b/dns.c index ecfaa63..4951774 100644 --- a/dns.c +++ b/dns.c @@ -30,13 +30,16 @@ #include #include +#include #include "announce.h" #include "util.h" #include "dns.h" +#include "cache.h" +#include "service.h" +#include "interface.h" -char *rdata_buffer; -static char *name_buffer; +static char name_buffer[MAX_NAME_LEN + 1]; const char* dns_type_string(uint16_t type) @@ -65,61 +68,38 @@ dns_type_string(uint16_t type) } void -dns_send_question(struct uloop_fd *u, char *question, int type) +dns_send_question(struct interface *iface, const 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; + 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; - 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); 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; - - 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); - - 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 (interface_send_packet(iface, iov, ARRAY_SIZE(iov)) < 0) fprintf(stderr, "failed to send question\n"); else DBG(1, "Q <- %s %s\n", dns_type_string(type), question); @@ -145,7 +125,7 @@ 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) @@ -157,34 +137,20 @@ 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 interface *iface, 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); @@ -214,7 +180,7 @@ 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 (interface_send_packet(iface, iov, (dns_answer_cnt * 3) + 1) < 0) fprintf(stderr, "failed to send question\n"); for (i = 0; i < dns_answer_cnt; i++) { @@ -225,7 +191,7 @@ 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; @@ -246,7 +212,7 @@ scan_name(uint8_t *buffer, int len) return offset + 1; } -struct dns_header* +static struct dns_header* dns_consume_header(uint8_t **data, int *len) { struct dns_header *h = (struct dns_header *) *data; @@ -267,7 +233,7 @@ dns_consume_header(uint8_t **data, int *len) return h; } -struct dns_question* +static struct dns_question* dns_consume_question(uint8_t **data, int *len) { struct dns_question *q = (struct dns_question *) *data; @@ -288,7 +254,7 @@ dns_consume_question(uint8_t **data, int *len) return q; } -struct dns_answer* +static struct dns_answer* dns_consume_answer(uint8_t **data, int *len) { struct dns_answer *a = (struct dns_answer *) *data; @@ -307,8 +273,8 @@ dns_consume_answer(uint8_t **data, int *len) return a; } -char* -dns_consume_name(uint8_t *base, int blen, uint8_t **data, int *len) +static char * +dns_consume_name(const uint8_t *base, int blen, uint8_t **data, int *len) { int nlen = scan_name(*data, *len); @@ -326,24 +292,110 @@ dns_consume_name(uint8_t *base, int blen, uint8_t **data, int *len) return name_buffer; } -int -dns_init(void) +static int +parse_answer(struct interface *iface, uint8_t *buffer, int len, uint8_t **b, int *rlen, int cache) { - name_buffer = malloc(MAX_NAME_LEN + 1); - rdata_buffer = malloc(MAX_DATA_LEN + 1); + char *name = dns_consume_name(buffer, len, b, rlen); + struct dns_answer *a; + uint8_t *rdata; - if (!name_buffer || !rdata_buffer) + if (!name) { + fprintf(stderr, "dropping: bad question\n"); return -1; + } - memset(name_buffer, 0, MAX_NAME_LEN + 1); - memset(rdata_buffer, 0, MAX_NAME_LEN + 1); + a = dns_consume_answer(b, rlen); + if (!a) { + fprintf(stderr, "dropping: bad question\n"); + return -1; + } + + rdata = *b; + if (a->rdlength > *rlen) { + fprintf(stderr, "dropping: bad question\n"); + return -1; + } + + *rlen -= a->rdlength; + *b += a->rdlength; + + if (cache) + cache_answer(iface, buffer, len, name, a, rdata); return 0; } +static void +parse_question(struct interface *iface, char *name, struct dns_question *q) +{ + char *host; + + DBG(1, "Q -> %s %s\n", dns_type_string(q->type), name); + + switch (q->type) { + case TYPE_ANY: + host = service_name("local"); + if (!strcmp(name, host)) + service_reply(iface, NULL); + break; + + case TYPE_PTR: + service_announce_services(iface, name); + service_reply(iface, name); + break; + + case TYPE_AAAA: + case TYPE_A: + host = strstr(name, ".local"); + if (host) + *host = '\0'; + if (!strcmp(hostname, name)) + service_reply_a(iface, q->type); + break; + }; +} + void -dns_cleanup(void) +dns_handle_packet(struct interface *iface, uint8_t *buffer, int len) { - free(name_buffer); - free(rdata_buffer); + struct dns_header *h; + uint8_t *b = buffer; + int rlen = len; + + h = dns_consume_header(&b, &rlen); + if (!h) { + fprintf(stderr, "dropping: bad header\n"); + return; + } + + while (h->questions-- > 0) { + char *name = dns_consume_name(buffer, len, &b, &rlen); + struct dns_question *q; + + if (!name) { + fprintf(stderr, "dropping: bad name\n"); + return; + } + + q = dns_consume_question(&b, &rlen); + if (!q) { + fprintf(stderr, "dropping: bad question\n"); + return; + } + + if (!(h->flags & FLAG_RESPONSE)) + parse_question(iface, name, q); + } + + if (!(h->flags & FLAG_RESPONSE)) + return; + + while (h->answers-- > 0) + parse_answer(iface, buffer, len, &b, &rlen, 1); + + while (h->authority-- > 0) + parse_answer(iface, buffer, len, &b, &rlen, 0); + + while (h->additional-- > 0) + parse_answer(iface, buffer, len, &b, &rlen, 1); }