Add missing srv.c and srv.h files

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@1086 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/srv.h

+/*
+ * Asterisk -- A telephony toolkit for Linux.
+ *
+ * ENUM support
+ * 
+ * Copyright (C) 1999, Mark Spencer
+ *
+ * Mark Spencer <markster@linux-support.net>
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License
+ */
+
+#ifndef _ASTERISK_SRV_H
+#define _ASTERISK_SRV_H
+#include <asterisk/channel.h>
+/* Lookup entry in SRV records Returns 1 if found, 0 if not found, -1 on hangup */
+extern int ast_get_srv(struct ast_channel *chan, char *host, int hostlen, int *port, const char *service);
+
+#endif

srv.c

+/*
+ * ENUM Support for Asterisk
+ *
+ * Copyright (C) 2003 Digium
+ *
+ * Written by Mark Spencer <markster@digium.com>
+ *
+ * Funding provided by nic.at
+ *
+ * Distributed under the terms of the GNU GPL
+ *
+ */
+
+#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 <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__));
+
+struct srv {
+	unsigned short priority;
+	unsigned short weight;
+	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;
+	len = olen = (int)src[0];
+	src++;
+	srclen--;
+	if (len > srclen) {
+		ast_log(LOG_WARNING, "Want %d, got %d\n", len, srclen);
+		return -1;
+	}
+	if (len > maxdatalen)
+		len = maxdatalen;
+	memcpy(data, src, len);
+	return olen + 1;
+}
+
+static int parse_srv(unsigned char *host, int hostlen, int *portno, unsigned char *answer, int len)
+{
+	int res = 0;
+	struct srv *srv = (struct srv *)answer;
+	char repl[256] = "";
+	char *oanswer = answer;
+	
+	if (len < sizeof(struct srv)) {
+		printf("Length too short\n");
+		return -1;
+	}
+	answer += sizeof(struct srv);
+	len -= sizeof(struct srv);
+
+	if ((res = dn_expand(oanswer,answer + len,answer, repl, sizeof(repl) - 1)) < 0) {
+		ast_log(LOG_WARNING, "Failed to expand hostname\n");
+		return -1;
+	}
+	if (res && strcmp(repl, ".")) {
+		if (host) {
+			strncpy(host, repl, hostlen - 1);
+			host[hostlen] = '\0';
+		}
+		if (portno)
+			*portno = ntohs(srv->portnum);
+		res = 1;
+	}
+		
+#if 0
+	if ((res = parse_ie(flags, sizeof(flags) - 1, answer, len)) < 0) {
+		ast_log(LOG_WARNING, "Failed to get flags\n");
+		return -1; 
+	} else { answer += res; len -= res; }
+	if ((res = parse_ie(services, sizeof(services) - 1, answer, len)) < 0) {
+		ast_log(LOG_WARNING, "Failed to get services\n");
+		return -1; 
+	} else { answer += res; len -= res; }
+	if ((res = parse_ie(regexp, sizeof(regexp) - 1, answer, len)) < 0)
+		return -1; else { answer += res; len -= res; }
+#if 0
+	printf("Flags: %s\n", flags);
+	printf("Services: %s\n", services);
+	printf("Regexp: %s\n", regexp);
+	printf("Repl: %s\n", repl);
+#endif
+	if (!strncmp(regexp, "!^.*$!", 6)) {
+		if (!strncmp(services, "E2U+voice:", 10)) {
+			if (regexp[strlen(regexp) - 1] == '!')
+				regexp[strlen(regexp) - 1] = '\0';
+#if 0
+			printf("Technology: %s\n", services + 10);
+			printf("Destination: %s\n", regexp + 6);
+#endif
+			strncpy(dst, regexp + 6, dstsize);
+			strncpy(tech, services + 10, techsize);
+		}
+	} else
+		ast_log(LOG_WARNING, "Non-total substitution not yet supported\n");
+#endif	 
+	return 0;
+}
+
+static int parse_answer(unsigned char *host, int hostlen, int *port, char *answer, int len)
+{
+	/*
+	 * This function is influenced by "ser" the SIP router.
+	 */
+	int x;
+	int res;
+	dns_HEADER *h;
+	struct dn_answer *ans;
+	host[0] = '\0';
+	*port = 0;
+#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(host, hostlen, port, answer, ntohs(ans->size)))
+				ast_log(LOG_WARNING, "Failed to parse srv :(\n");
+			if (strlen(host))
+				return 0;
+		}
+		answer += ntohs(ans->size);
+	}
+	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];
+
+	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;
+	}
+	if (chan)
+		ret |= ast_autoservice_stop(chan);
+	res_nclose(&srvstate);
+	return ret;
+}