loose.c

用来作为linux中SIP SERVER,完成VOIP网络电话中服务器的功能

		pkg_free(s);
		LOG(L_ERR, "save_ruri: Cannot insert lump\n");
		return -4;
	}

	return 0;
}


/*
 * Logic necessary to forward request to strict routers
 *
 * Returns 0 on success, negative number on an error
 */
static inline int handle_sr(struct sip_msg* _m, struct hdr_field* _hdr, rr_t* _r)
{
	str* uri;
	char* rem_off;
	int rem_len;

	uri = &_r->nameaddr.uri;

	     /* Next hop is strict router, save R-URI here */
	if (save_ruri(_m) < 0) {
		LOG(L_ERR, "handle_sr: Error while saving Request-URI\n");
		return -1;
	}
	
	     /* Put the first Route in Request-URI */
	if (rewrite_uri(_m, uri) < 0) {
		LOG(L_ERR, "handle_sr: Error while rewriting request URI\n");
		return -2;
	}

	if (!_r->next) {
		rem_off = _hdr->name.s;
		rem_len = _hdr->len;
	} else {
		rem_off = _hdr->body.s;
		rem_len = _r->next->nameaddr.name.s - _hdr->body.s;
	}

	if (!del_lump(_m, rem_off - _m->buf, rem_len, 0)) {
		LOG(L_ERR, "handle_sr: Can't remove Route HF\n");
		return -9;
	}			

	return 0;
}


/*
 * Find last route in the last Route header field,
 * if there was a previous route in the last Route header
 * field, it will be saved in _p parameter
 */
static inline int find_rem_target(struct sip_msg* _m, struct hdr_field** _h, rr_t** _l, rr_t** _p)
{
	struct hdr_field* ptr, *last;

	if (parse_headers(_m, HDR_EOH, 0) == -1) {
		LOG(L_ERR, "find_rem_target: Error while parsing message header\n");
		return -1;
	}

	ptr = _m->route;
	last = 0;

	while(ptr) {
		if (ptr->type == HDR_ROUTE) last = ptr;
		ptr = ptr->next;
	}

	if (last) {
		if (parse_rr(last) < 0) {
			LOG(L_ERR, "find_rem_target: Error while parsing last Route HF\n");
			return -2;
		}

		*_p = 0;
		*_l = (rr_t*)last->parsed;
		while ((*_l)->next) {
			*_p = *_l;
			*_l = (*_l)->next;
		}
		return 0;
	} else {
		LOG(L_ERR, "find_rem_target: Can't find last Route HF\n");
		return 1;
	}
}


/*
 * Previous hop was a strict router, handle this case
 */
static inline int after_strict(struct sip_msg* _m)
{
	int res, rem_len;
	struct hdr_field* hdr;
	struct sip_uri puri;
	rr_t* rt, *prev;
	char* rem_off;
	str* uri;

	hdr = _m->route;
	rt = (rr_t*)hdr->parsed;
	uri = &rt->nameaddr.uri;

	if (parse_uri(uri->s, uri->len, &puri) < 0) {
		LOG(L_ERR, "after_strict: Error while parsing the first route URI\n");
		return RR_ERROR;
	}

#ifdef ENABLE_USER_CHECK
	if (is_myself(&puri.user, &puri.host, puri.port_no))
#else
	if (is_myself(&puri.host, puri.port_no))
#endif
	{
		     /*	if (enable_double_rr && is_2rr(&_ruri->params)) { */ 
	      /* DBG("ras(): Removing 2nd URI of mine: '%.*s'\n", rt->nameaddr.uri.len, ZSW(rt->nameaddr.uri.s)); */
 		if (!rt->next) {
			     /* No next route in the same header, remove the whole header
			      * field immediately
			      */
			if (!del_lump(_m, hdr->name.s - _m->buf, hdr->len, 0)) {
				LOG(L_ERR, "after_strict: Cannot remove Route HF\n");
				return RR_ERROR;
			}
			res = find_next_route(_m, &hdr);
			if (res < 0) {
				LOG(L_ERR, "after_strict: Error while searching next route\n");
				return RR_ERROR;
			}
			if (res > 0) { /* No next route found */
				DBG("after_strict: No next URI found\n");
				return NOT_RR_DRIVEN;
			}
			rt = (rr_t*)hdr->parsed;
		} else rt = rt->next;
	}

	uri = &rt->nameaddr.uri;
	if (parse_uri(uri->s, uri->len, &puri) == -1) {
		LOG(L_ERR, "after_strict: Error while parsing URI\n");
		return RR_ERROR;
	}

	if (is_strict(&puri.params)) {
		DBG("after_strict: Next hop: '%.*s' is strict router\n", uri->len, ZSW(uri->s));
		     /* Previous hop was a strict router and the next hop is strict
		      * router too. There is no need to save R-URI again because it
		      * is saved already. In fact, in this case we will behave exactly
		      * like a strict router.
		      */

		     /* Note: when there is only one Route URI left (endpoint), it will
		      * always be a strict router because endpoints don't use ;lr parameter
		      * In this case we will simply put the URI in R-URI and forward it, which
		      * will work perfectly
		      */
		if (rewrite_uri(_m, uri) < 0) {
			LOG(L_ERR, "after_strict: Error while rewriting request URI\n");
			return RR_ERROR;
		}
		
		if (rt->next) {
			rem_off = hdr->body.s;
			rem_len = rt->next->nameaddr.name.s - hdr->body.s;
		} else {
			rem_off = hdr->name.s;
			rem_len = hdr->len;
		}
		if (!del_lump(_m, rem_off - _m->buf, rem_len, 0)) {
			LOG(L_ERR, "after_strict: Cannot remove Route HF\n");
			return RR_ERROR;
		}
	} else {
		DBG("after_strict: Next hop: '%.*s' is loose router\n", uri->len, ZSW(uri->s));

		if (set_dst_uri(_m, uri) < 0) {
			LOG(L_ERR, "after_strict: Error while setting dst_uri\n");
			return RR_ERROR;
		}

		     /* Next hop is a loose router - Which means that is is not endpoint yet
		      * In This case we have to recover from previous strict routing, that 
		      * means we have to find the last Route URI and put in in R-URI and 
		      * remove the last Route URI.
		      */
		if (rt != hdr->parsed) {
			     /* There is a previous route uri which was 2nd uri of mine
			      * and must be removed here
			      */
			rem_off = hdr->body.s;
			rem_len = rt->nameaddr.name.s - hdr->body.s;
			if (!del_lump(_m, rem_off - _m->buf, rem_len, 0)) {
				LOG(L_ERR, "after_strict: Can't remove Route HF\n");
				return RR_ERROR;
			}			
		}


		res = find_rem_target(_m, &hdr, &rt, &prev);
		if (res < 0) {
			LOG(L_ERR, "after_strict: Error while looking for last Route URI\n");
			return RR_ERROR;
		} else if (res > 0) {
			     /* No remote target is an error */
			return RR_ERROR;
		}

		uri = &rt->nameaddr.uri;
		if (rewrite_uri(_m, uri) < 0) {
			LOG(L_ERR, "after_strict: Can't rewrite R-URI\n");
			return RR_ERROR;
		}
		
		     /* The first character if uri will be either '<' when it is the only URI in a
		      * Route header field or ',' if there is more than one URI in the header field
		      */
		DBG("after_strict: The last route URI: '%.*s'\n", 
		    rt->nameaddr.uri.len, ZSW(rt->nameaddr.uri.s));

		if (prev) {
			rem_off = prev->nameaddr.name.s + prev->len;
			rem_len = rt->nameaddr.name.s + rt->len - rem_off;
		} else {
			rem_off = hdr->name.s;
			rem_len = hdr->len;
		}
		if (!del_lump(_m, rem_off - _m->buf, rem_len, 0)) {
			LOG(L_ERR, "after_strict: Can't remove Route HF\n");
			return RR_ERROR;
		}
	}
	
	return RR_DRIVEN;
}


static inline int after_loose(struct sip_msg* _m, int preloaded)
{
	struct hdr_field* hdr;
	struct sip_uri puri;
	rr_t* rt;
	int res;	
#ifdef ENABLE_USER_CHECK
	int ret;
#endif
	str* uri;

	hdr = _m->route;
	rt = (rr_t*)hdr->parsed;
	uri = &rt->nameaddr.uri;

	if (parse_uri(uri->s, uri->len, &puri) < 0) {
		LOG(L_ERR, "after_loose: Error while parsing the first route URI\n");
		return RR_ERROR;
	}

	     /* IF the URI was added by me, remove it */
#ifdef ENABLE_USER_CHECK
	ret=is_myself(&puri.user, &puri.host, puri.port_no);
	if (ret>0)
#else
	if (is_myself(&puri.host, puri.port_no))
#endif
	{
		DBG("after_loose: Topmost route URI: '%.*s' is me\n", uri->len, ZSW(uri->s));
		if (!rt->next) {
			     /* No next route in the same header, remove the whole header
			      * field immediately
			      */
			if (!del_lump(_m, hdr->name.s - _m->buf, hdr->len, 0)) {
				LOG(L_ERR, "after_loose: Can't remove Route HF\n");
				return RR_ERROR;
			}
			res = find_next_route(_m, &hdr);
			if (res < 0) {
				LOG(L_ERR, "after_loose: Error while finding next route\n");
				return RR_ERROR;
			}
			if (res > 0) { /* No next route found */
				DBG("after_loose: No next URI found\n");
				return (preloaded ? NOT_RR_DRIVEN : RR_DRIVEN);
			}
			rt = (rr_t*)hdr->parsed;
		} else rt = rt->next;
		
		if (enable_double_rr && is_2rr(&puri.params)) {
			if (!rt->next) {
				     /* No next route in the same header, remove the whole header
				      * field immediately
				      */
				if (!del_lump(_m, hdr->name.s - _m->buf, hdr->len, 0)) {
					LOG(L_ERR, "after_loose: Can't remove Route HF\n");
					return RR_ERROR;
				}
				res = find_next_route(_m, &hdr);
				if (res < 0) {
					LOG(L_ERR, "after_loose: Error while finding next route\n");
					return RR_ERROR;
				}
				if (res > 0) { /* No next route found */
					DBG("after_loose: No next URI found\n");
					return (preloaded ? NOT_RR_DRIVEN : RR_DRIVEN);
				}
				rt = (rr_t*)hdr->parsed;
			} else rt = rt->next;
		}
		
		uri = &rt->nameaddr.uri;
		if (parse_uri(uri->s, uri->len, &puri) < 0) {
			LOG(L_ERR, "after_loose: Error while parsing the first route URI\n");
			return RR_ERROR;
		}
	} else {
#ifdef ENABLE_USER_CHECK
		/* check if it the ignored user */
		if(ret < 0)
			return NOT_RR_DRIVEN;
#endif	
		DBG("after_loose: Topmost URI is NOT myself\n");
	}
	
	DBG("after_loose: URI to be processed: '%.*s'\n", uri->len, ZSW(uri->s));
	if (is_strict(&puri.params)) {
		DBG("after_loose: Next URI is a strict router\n");
		if (handle_sr(_m, hdr, rt) < 0) {
			LOG(L_ERR, "after_loose: Error while handling strict router\n");
			return RR_ERROR;
		}
	} else {
		     /* Next hop is loose router */
		DBG("after_loose: Next URI is a loose router\n");

		if (set_dst_uri(_m, uri) < 0) {
			LOG(L_ERR, "after_loose: Error while setting dst_uri\n");
			return RR_ERROR;
		}

		     /* There is a previous route uri which was 2nd uri of mine
		      * and must be removed here
		      */
		if (rt != hdr->parsed) {
			if (!del_lump(_m, hdr->body.s - _m->buf, rt->nameaddr.name.s - hdr->body.s, 0)) {
				LOG(L_ERR, "after_loose: Can't remove Route HF\n");
				return RR_ERROR;
			}			
		}
	}

	return RR_DRIVEN;
}


/*
 * Do loose routing as defined in RFC3621
 */
int loose_route(struct sip_msg* _m, char* _s1, char* _s2)
{
	int ret;

	if (find_first_route(_m) != 0) {
		DBG("loose_route: There is no Route HF\n");
		return -1;
	}
		
	if (parse_sip_msg_uri(_m) == -1) {
		LOG(L_ERR, "loose_route: Error while parsing Request URI\n");
		return -1;
	}

	ret = is_preloaded(_m);
	if (ret < 0) {
		return -1;
	} else if (ret == 1) {
		return after_loose(_m, 1);
	} else {
#ifdef ENABLE_USER_CHECK
		if (is_myself(&_m->parsed_uri, &_m->parsed_uri.host, &_m->parsed_uri.port_no)) {
#else
		if (is_myself(&_m->parsed_uri.host, _m->parsed_uri.port_no)) {
#endif
			return after_strict(_m);
		} else {
			return after_loose(_m, 0);
		}
	}
}