update DNS resolver
[asterisk/asterisk.git] / srv.c
diff --git a/srv.c b/srv.c
index c6365e3..25011ad 100755 (executable)
--- a/srv.c
+++ b/srv.c
  *
  */
 
-#include <string.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <stdlib.h>
 #include <sys/types.h>
-#include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/nameser.h>
 #include <resolv.h>
-#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
 
+#include <asterisk/channel.h>
 #include <asterisk/logger.h>
-#include <asterisk/options.h>
 #include <asterisk/srv.h>
-#include <asterisk/channel.h>
-#include <asterisk/config.h>
-
-#define MAX_SIZE 4096
-
-typedef struct {
-       unsigned        id :16;         /* query identification number */
-#if BYTE_ORDER == BIG_ENDIAN
-                       /* fields in third byte */
-       unsigned        qr: 1;          /* response flag */
-       unsigned        opcode: 4;      /* purpose of message */
-       unsigned        aa: 1;          /* authoritive answer */
-       unsigned        tc: 1;          /* truncated message */
-       unsigned        rd: 1;          /* recursion desired */
-                       /* fields in fourth byte */
-       unsigned        ra: 1;          /* recursion available */
-       unsigned        unused :1;      /* unused bits (MBZ as of 4.9.3a3) */
-       unsigned        ad: 1;          /* authentic data from named */
-       unsigned        cd: 1;          /* checking disabled by resolver */
-       unsigned        rcode :4;       /* response code */
-#endif
-#if BYTE_ORDER == LITTLE_ENDIAN || BYTE_ORDER == PDP_ENDIAN
-                       /* fields in third byte */
-       unsigned        rd :1;          /* recursion desired */
-       unsigned        tc :1;          /* truncated message */
-       unsigned        aa :1;          /* authoritive answer */
-       unsigned        opcode :4;      /* purpose of message */
-       unsigned        qr :1;          /* response flag */
-                       /* fields in fourth byte */
-       unsigned        rcode :4;       /* response code */
-       unsigned        cd: 1;          /* checking disabled by resolver */
-       unsigned        ad: 1;          /* authentic data from named */
-       unsigned        unused :1;      /* unused bits (MBZ as of 4.9.3a3) */
-       unsigned        ra :1;          /* recursion available */
-#endif
-                       /* remaining bytes */
-       unsigned        qdcount :16;    /* number of question entries */
-       unsigned        ancount :16;    /* number of answer entries */
-       unsigned        nscount :16;    /* number of authority entries */
-       unsigned        arcount :16;    /* number of resource entries */
-} dns_HEADER;
-
-struct dn_answer {
-       unsigned short rtype;
-       unsigned short class;
-       unsigned int ttl;
-       unsigned short size;
-} __attribute__ ((__packed__));
+#include <asterisk/dns.h>
+#include <asterisk/options.h>
 
 struct srv {
        unsigned short priority;
@@ -80,29 +31,6 @@ struct srv {
        unsigned short portnum;
 } __attribute__ ((__packed__));
 
-static int skip_name(unsigned char *s, int len)
-{
-       /* Shamelessly take from SER */
-       int x = 0;
-       while(x < len) {
-               if (!*s) {
-                       s++;
-                       x++;
-                       break;
-               }
-               if (((*s) & 0xc0) == 0xc0) {
-                       s += 2;
-                       x += 2;
-                       break;
-               }
-               x += *s + 1;
-               s += *s + 1;
-       }
-       if (x >= len)
-               return -1;
-       return x;
-}
-
 static int parse_ie(unsigned char *data, int maxdatalen, unsigned char *src, int srclen)
 {
        int len, olen;
@@ -149,124 +77,45 @@ static int parse_srv(unsigned char *host, int hostlen, int *portno, unsigned cha
        return(-1);
 }
 
-static int parse_answer(unsigned char *host, int hostlen, int *port, char *answer, int len)
+struct srv_context {
+       char *host;
+       int hostlen;
+       int *port;
+};
+
+static int srv_callback(void *context, u_char *answer, int len, u_char *fullanswer)
 {
-       /*
-        * This function is influenced by "ser" the SIP router.
-        */
-       int x;
-       int res;
-       dns_HEADER *h;
-       struct dn_answer *ans;
-/*     int lastlit = 1; */
-       char *oanswer = answer;
-       host[0] = '\0';
-       *port = 0;
+       struct srv_context *c = (struct srv_context *)context;
 
-#if 0
-       for (x=0;x<len;x++) {
-               if ((answer[x] < 32) || (answer[x] > 127)) {
-                       if (lastlit)
-                               printf("\"");
-                       printf(" 0x%02x", answer[x]);
-                       lastlit = 0;
-               } else {
-                       if (!lastlit) 
-                               printf(" \"");
-                       printf("%c", answer[x]);
-                       lastlit = 1;
-               }
-       }
-       printf("\n");
-#endif 
-       h = (dns_HEADER *)answer;
-       /* Skip over DNS header */
-       answer += sizeof(dns_HEADER);
-       len -= sizeof(dns_HEADER);
-#if 0
-       printf("Query count: %d\n", ntohs(h->qdcount));
-#endif
-       for (x=0;x<ntohs(h->qdcount);x++) {
-               if ((res = skip_name(answer, len)) < 0) {
-                       ast_log(LOG_WARNING, "Couldn't skip over name\n");
-                       return -1;
-               }
-               answer += res;
-               len -= res;
-               answer += 4;    /* Skip QCODE / QCLASS */
-               len -= 4;
-               if (len < 0) {
-                       ast_log(LOG_WARNING, "Strange query size\n");
-                       return -1;
-               }
-       }
-#if 0
-       printf("Length remaining: %d, already at %04x\n", len, 0x2a + (answer - oanswer));
-       printf("Answer count: %d\n", ntohs(h->ancount));
-       printf("Looking for %d/%d\n", C_IN, T_SRV);
-       printf("Answer so far: %02x %02x %02x %02x %02x %02x\n", answer[0], answer[1], answer[2], answer[3], answer[4], answer[5]);
-#endif
-       for (x=0;x<ntohs(h->ancount);x++) {
-               if ((res = skip_name(answer, len)) < 0) {
-                       ast_log(LOG_WARNING, "Failed to skip name :(\n");
-                       return -1;
-               }
-               answer += res;
-               len -= res;
-               ans = (struct dn_answer *)answer;
-               answer += sizeof(struct dn_answer);
-               len -= sizeof(struct dn_answer);
-               if (len < 0)
-                       return -1;
-#if 0
-               printf("Type: %d (%04x), class: %d (%04x), ttl: %d (%08x), length: %d (%04x)\n", ntohs(ans->rtype), ntohs(ans->rtype), ntohs(ans->class), ntohs(ans->class),
-                       ntohl(ans->ttl), ntohl(ans->ttl), ntohs(ans->size), ntohs(ans->size));
-#endif                 
-               len -= ntohs(ans->size);
-               if (len < 0) {
-                       ast_log(LOG_WARNING, "Length exceeds frame by %d\n", -len);
-                       return -1;
-               }
-               if ((ntohs(ans->class) == C_IN) && (ntohs(ans->rtype) == T_SRV)) {
+       if (parse_srv(c->host, c->hostlen, c->port, answer, len, fullanswer))
+               ast_log(LOG_WARNING, "Failed to parse srv\n");
 
-                       if (parse_srv(host, hostlen, port, answer, ntohs(ans->size),oanswer))
-                               ast_log(LOG_WARNING, "Failed to parse srv :(\n");
+       if (strlen(c->host))
+               return 1;
 
-                       if (strlen(host))
-                               return 0;
-               }
-               answer += ntohs(ans->size);
-       }
-       return 0;
+    return 0;
 }
 
 int ast_get_srv(struct ast_channel *chan, char *host, int hostlen, int *port, const char *service)
 {
-       int res;
-       int ret = -1;
-       struct __res_state srvstate;
-       char answer[MAX_SIZE];
+       struct srv_context context;
+       int ret;
+
+       context.host = host;
+       context.hostlen = hostlen;
+       context.port = port;
 
-       if (*port)
-               *port = 0;
-       res_ninit(&srvstate);   
        if (chan && ast_autoservice_start(chan) < 0)
                return -1;
-       res = res_nsearch(&srvstate, service, C_IN, T_SRV, answer, sizeof(answer));
-       if (res > 0) {
-               if ((res = parse_answer(host, hostlen, port, answer, res))) {
-                       ast_log(LOG_WARNING, "Parse error returned %d\n", res);
-                       ret = 0;
-               } else {
-                       ast_log(LOG_DEBUG, "Found host '%s', port '%d'\n", host, *port);
-                       ret = 1;
-               }
-       } else {
-               ast_log(LOG_DEBUG, "No such service found: %s (%s)\n", service, strerror(errno));
-               ret = 0;
-       }
+
+       ret = ast_search_dns(&context, service, C_IN, T_SRV, srv_callback);
+
        if (chan)
                ret |= ast_autoservice_stop(chan);
-       res_nclose(&srvstate);
+
+       if (ret <= 0)
+               return ret;
+       strcpy(host, "");
+    *port = -1;
        return ret;
 }