nathelper.c

来自「性能优秀的SIP Proxy」· C语言 代码 · 共 2,354 行 · 第 1/5 页

			}
			memset(pnode, 0, sizeof(*pnode));
			pnode->rn_recheck_ticks = 0;
			pnode->rn_weight = weight;
			pnode->rn_umode = 0;
			pnode->rn_fd = -1;
			pnode->rn_disabled = 0;
			pnode->rn_url = pkg_malloc(p2 - p1 + 1);
			if (pnode->rn_url == NULL) {
				LOG(L_ERR, "nathelper: Can't allocate memory\n");
				return -1;
			}
			memmove(pnode->rn_url, p1, p2 - p1);
			pnode->rn_url[p2 - p1] = 0;
			if (rtpp_list.rn_first == NULL) {
				rtpp_list.rn_first = pnode;
			} else {
				rtpp_list.rn_last->rn_next = pnode;
			}
			rtpp_list.rn_last = pnode;
			++rtpp_node_count;
			/* Leave only address in rn_address */
			pnode->rn_address = pnode->rn_url;
			if (strncmp(pnode->rn_address, "udp:", 4) == 0) {
				pnode->rn_umode = 1;
				pnode->rn_address += 4;
			} else if (strncmp(pnode->rn_address, "udp6:", 5) == 0) {
				pnode->rn_umode = 6;
				pnode->rn_address += 5;
			} else if (strncmp(pnode->rn_address, "unix:", 5) == 0) {
				pnode->rn_umode = 0;
				pnode->rn_address += 5;
			}
		}
	}

	return 0;
}

static int
child_init(int rank)
{
	int n;
	char *cp;
	struct addrinfo hints, *res;
	struct rtpp_node *pnode;

	/* Iterate known RTP proxies - create sockets */
	mypid = getpid();
	for (pnode = rtpp_list.rn_first; pnode != NULL; pnode = pnode->rn_next) {
		char *old_colon;

		if (pnode->rn_umode == 0)
			goto rptest;
		/*
		 * This is UDP or UDP6. Detect host and port; lookup host;
		 * do connect() in order to specify peer address
		 */
		old_colon = cp = strrchr(pnode->rn_address, ':');
		if (cp != NULL) {
			old_colon = cp;
			*cp = '\0';
			cp++;
		}
		if (cp == NULL || *cp == '\0')
			cp = CPORT;

		memset(&hints, 0, sizeof(hints));
		hints.ai_flags = 0;
		hints.ai_family = (pnode->rn_umode == 6) ? AF_INET6 : AF_INET;
		hints.ai_socktype = SOCK_DGRAM;
		if ((n = getaddrinfo(pnode->rn_address, cp, &hints, &res)) != 0) {
			LOG(L_ERR, "nathelper: getaddrinfo: %s\n", gai_strerror(n));
			return -1;
		}
		if (old_colon)
			*old_colon = ':'; /* restore rn_address */

		pnode->rn_fd = socket((pnode->rn_umode == 6)
		    ? AF_INET6 : AF_INET, SOCK_DGRAM, 0);
		if (pnode->rn_fd == -1) {
			LOG(L_ERR, "nathelper: can't create socket\n");
			freeaddrinfo(res);
			return -1;
		}

		if (connect(pnode->rn_fd, res->ai_addr, res->ai_addrlen) == -1) {
			LOG(L_ERR, "nathelper: can't connect to a RTP proxy\n");
			close(pnode->rn_fd);
			pnode->rn_fd = -1;
			freeaddrinfo(res);
			return -1;
		}
		freeaddrinfo(res);
rptest:
		pnode->rn_disabled = rtpp_test(pnode, 0, 1);
	}

	if (rtpproxy_disable)
		rtpproxy_disable_tout = -1;

	return 0;
}

static int
isnulladdr(str *sx, int pf)
{
	char *cp;

	if (pf == AF_INET6) {
		for(cp = sx->s; cp < sx->s + sx->len; cp++)
			if (*cp != '0' && *cp != ':')
				return 0;
		return 1;
	}
	return (sx->len == 7 && memcmp("0.0.0.0", sx->s, 7) == 0);
}

/*
 * ser_memmem() returns the location of the first occurrence of data
 * pattern b2 of size len2 in memory block b1 of size len1 or
 * NULL if none is found. Obtained from NetBSD.
 */
static void *
ser_memmem(const void *b1, const void *b2, size_t len1, size_t len2)
{
	/* Initialize search pointer */
	char *sp = (char *) b1;

	/* Initialize pattern pointer */
	char *pp = (char *) b2;

	/* Initialize end of search address space pointer */
	char *eos = sp + len1 - len2;

	/* Sanity check */
	if(!(b1 && b2 && len1 && len2))
		return NULL;

	while (sp <= eos) {
		if (*sp == *pp)
			if (memcmp(sp, pp, len2) == 0)
				return sp;

			sp++;
	}

	return NULL;
}

/*
 * Some helper functions taken verbatim from tm module.
 */

/*
 * Extract tag from To header field of a response
 * assumes the to header is already parsed, so
 * make sure it really is before calling this function
 */
static inline int
get_to_tag(struct sip_msg* _m, str* _tag)
{

	if (!_m->to) {
		LOG(L_ERR, "get_to_tag(): To header field missing\n");
		return -1;
	}

	if (get_to(_m)->tag_value.len) {
		_tag->s = get_to(_m)->tag_value.s;
		_tag->len = get_to(_m)->tag_value.len;
	} else {
		_tag->len = 0;
	}

	return 0;
}


/*
 * Extract tag from From header field of a request
 */
static inline int
get_from_tag(struct sip_msg* _m, str* _tag)
{

	if (parse_from_header(_m)<0) {
		LOG(L_ERR, "get_from_tag(): Error while parsing From header\n");
		return -1;
	}

	if (get_from(_m)->tag_value.len) {
		_tag->s = get_from(_m)->tag_value.s;
		_tag->len = get_from(_m)->tag_value.len;
	} else {
		_tag->len = 0;
	}

	return 0;
}

/*
 * Extract Call-ID value
 * assumes the callid header is already parsed
 * (so make sure it is, before calling this function or
 *  it might fail even if the message _has_ a callid)
 */
static inline int
get_callid(struct sip_msg* _m, str* _cid)
{

	if ((parse_headers(_m, HDR_CALLID_F, 0) == -1)) {
		LOG(L_ERR, "get_callid(): parse_headers() failed\n");
		return -1;
	}

	if (_m->callid == NULL) {
		LOG(L_ERR, "get_callid(): Call-ID not found\n");
		return -1;
	}

	_cid->s = _m->callid->body.s;
	_cid->len = _m->callid->body.len;
	trim(_cid);
	return 0;
}

/*
 * Extract URI from the Contact header field
 */
static inline int
get_contact_uri(struct sip_msg* _m, struct sip_uri *uri, contact_t** _c)
{

	if ((parse_headers(_m, HDR_CONTACT_F, 0) == -1) || !_m->contact)
		return -1;
	if (!_m->contact->parsed && parse_contact(_m->contact) < 0) {
		LOG(L_ERR, "get_contact_uri: Error while parsing Contact body\n");
		return -1;
	}
	*_c = ((contact_body_t*)_m->contact->parsed)->contacts;
	if (*_c == NULL)
		/* no contacts found */
		return -1;

	if (parse_uri((*_c)->uri.s, (*_c)->uri.len, uri) < 0 || uri->host.len <= 0) {
		LOG(L_ERR, "get_contact_uri: Error while parsing Contact URI\n");
		return -1;
	}
	return 0;
}

/*
 * Replaces ip:port pair in the Contact: field with the source address
 * of the packet.
 */
static int
fix_nated_contact_f(struct sip_msg* msg, char* str1, char* str2)
{
	int offset, len, len1;
	char *cp, *buf, temp[2];
	contact_t *c;
	struct lump *anchor;
	struct sip_uri uri;
	str hostport;

	if (get_contact_uri(msg, &uri, &c) == -1)
		return -1;
	if ((c->uri.s < msg->buf) || (c->uri.s > (msg->buf + msg->len))) {
		LOG(L_ERR, "ERROR: you can't call fix_nated_contact twice, "
		    "check your config!\n");
		return -1;
	}

	offset = c->uri.s - msg->buf;
	anchor = del_lump(msg, offset, c->uri.len, HDR_CONTACT_T);
	if (anchor == 0)
		return -1;

	hostport = uri.host;
	if (uri.port.len > 0)
		hostport.len = uri.port.s + uri.port.len - uri.host.s;

	cp = ip_addr2a(&msg->rcv.src_ip);
	len = c->uri.len + strlen(cp) + 6 /* :port */ - hostport.len + 1;
	buf = pkg_malloc(len);
	if (buf == NULL) {
		LOG(L_ERR, "ERROR: fix_nated_contact: out of memory\n");
		return -1;
	}
	temp[0] = hostport.s[0];
	temp[1] = c->uri.s[c->uri.len];
	c->uri.s[c->uri.len] = hostport.s[0] = '\0';
	len1 = snprintf(buf, len, "%s%s:%d%s", c->uri.s, cp, msg->rcv.src_port,
	    hostport.s + hostport.len);
	if (len1 < len)
		len = len1;
	hostport.s[0] = temp[0];
	c->uri.s[c->uri.len] = temp[1];
	if (insert_new_lump_after(anchor, buf, len, HDR_CONTACT_T) == 0) {
		pkg_free(buf);
		return -1;
	}
	c->uri.s = buf;
	c->uri.len = len;

	return 1;
}

inline static int
fixup_str2int( void** param, int param_no)
{
	unsigned long go_to;
	int err;

	if (param_no == 1 || param_no == 2) {
		go_to = str2s(*param, strlen(*param), &err);
		if (err == 0) {
			pkg_free(*param);
			*param = (void *)go_to;
			return 0;
		} else {
			LOG(L_ERR, "ERROR: fixup_str2int: bad number <%s>\n",
				(char *)(*param));
			return E_CFG;
		}
	}
	return 0;
}

/*
 * Test if IP address pointed to by saddr belongs to RFC1918 networks
 */
static inline int
is1918addr(str *saddr)
{
	struct in_addr addr;
	uint32_t netaddr;
	int i, rval;
	char backup;

	rval = -1;
	backup = saddr->s[saddr->len];
	saddr->s[saddr->len] = '\0';
	if (inet_aton(saddr->s, &addr) != 1)
		goto theend;
	netaddr = ntohl(addr.s_addr);
	for (i = 0; nets_1918[i].cnetaddr != NULL; i++) {
		if ((netaddr & nets_1918[i].mask) == nets_1918[i].netaddr) {
			rval = 1;
			goto theend;
		}
	}
	rval = 0;

theend:
	saddr->s[saddr->len] = backup;
	return rval;
}

/*
 * test for occurrence of RFC1918 IP address in Contact HF
 */
static int
contact_1918(struct sip_msg* msg)
{
	struct sip_uri uri;
	contact_t* c;

	if (get_contact_uri(msg, &uri, &c) == -1)
		return -1;

	return (is1918addr(&(uri.host)) == 1) ? 1 : 0;
}

/*
 * test for occurrence of RFC1918 IP address in SDP
 */
static int
sdp_1918(struct sip_msg* msg)
{
	str body, ip;
	int pf;

	if (extract_body(msg, &body) == -1) {
		LOG(L_ERR,"ERROR: sdp_1918: cannot extract body from msg!\n");
		return 0;
	}
	if (extract_mediaip(&body, &ip, &pf,"c=") == -1) {
		LOG(L_ERR, "ERROR: sdp_1918: can't extract media IP from the SDP\n");
		return 0;
	}
	if (pf != AF_INET || isnulladdr(&ip, pf))
		return 0;

	return (is1918addr(&ip) == 1) ? 1 : 0;
}

/*
 * test for occurrence of RFC1918 IP address in top Via
 */
static int
via_1918(struct sip_msg* msg)
{

	return (is1918addr(&(msg->via1->host)) == 1) ? 1 : 0;
}

static int
nat_uac_test_f(struct sip_msg* msg, char* str1, char* str2)
{
	int tests;

	tests = (int)(long)str1;

	/* return true if any of the NAT-UAC tests holds */

	/* test if the source port is different from the port in Via */
	if ((tests & NAT_UAC_TEST_RPORT) &&
		 (msg->rcv.src_port!=(msg->via1->port?msg->via1->port:SIP_PORT)) ){
		return 1;
	}
	/*
	 * test if source address of signaling is different from
	 * address advertised in Via
	 */
	if ((tests & NAT_UAC_TEST_RCVD) && received_test(msg))
		return 1;
	/*
	 * test for occurrences of RFC1918 addresses in Contact
	 * header field
	 */
	if ((tests & NAT_UAC_TEST_C_1918) && (contact_1918(msg)>0))
		return 1;
	/*
	 * test for occurrences of RFC1918 addresses in SDP body
	 */
	if ((tests & NAT_UAC_TEST_S_1918) && sdp_1918(msg))
		return 1;
	/*
	 * test for occurrences of RFC1918 addresses top Via
	 */
	if ((tests & NAT_UAC_TEST_V_1918) && via_1918(msg))
		return 1;

	/* no test succeeded */
	return -1;

}

#define	ADD_ADIRECTION	0x01
#define	FIX_MEDIP	0x02
#define	ADD_ANORTPPROXY	0x04
#define	FIX_ORGIP	0x08

#define	ADIRECTION	"a=direction:active\r\n"
#define	ADIRECTION_LEN	(sizeof(ADIRECTION) - 1)

#define	AOLDMEDIP	"a=oldmediaip:"
#define	AOLDMEDIP_LEN	(sizeof(AOLDMEDIP) - 1)

#define	AOLDMEDIP6	"a=oldmediaip6:"
#define	AOLDMEDIP6_LEN	(sizeof(AOLDMEDIP6) - 1)

#define	AOLDMEDPRT	"a=oldmediaport:"
#define	AOLDMEDPRT_LEN	(sizeof(AOLDMEDPRT) - 1)

#define	ANORTPPROXY	"a=nortpproxy:yes\r\n"
#define	ANORTPPROXY_LEN	(sizeof(ANORTPPROXY) - 1)