nathelper: set via branch according to "z9hG4bK..." format (instead of "branch=0")

modules/nathelper/sip_pinger.h

@@ -116,6 +116,9 @@ static inline char* build_sipping(str *curi, struct socket_info* s, str *path,
 								str *ruid, unsigned int aorhash, int *len_p)
 {
 #define s_len(_s) (sizeof(_s)-1)
+#define MAX_BRANCHID 9999999
+#define MIN_BRANCHID 1000000
+#define LEN_BRANCHID 7  /* NOTE: this must be sync with the MX and MIN values !! */
 	static char buf[MAX_SIPPING_SIZE];
 	char *p;
 	int len;
@@ -135,7 +138,7 @@ static inline char* build_sipping(str *curi, struct socket_info* s, str *path,
 	if ( sipping_method.len + 1 + curi->len + s_len(" SIP/2.0"CRLF) +
 		s_len("Via: SIP/2.0/UDP ") + vaddr.len +
 				((s->address.af==AF_INET6)?2:0) +
-				1 + vport.len + s_len(";branch=0") +
+				1 + vport.len + s_len(";branch=z9hG4bK") + LEN_BRANCHID +
 		(path->len ? (s_len(CRLF"Route: ") + path->len) : 0) +
 		s_len(CRLF"From: ") +  sipping_from.len + s_len(";tag=") +
 				ruid->len + 1 + 8 + 1 + 8 +
@@ -164,13 +167,16 @@ static inline char* build_sipping(str *curi, struct socket_info* s, str *path,
 	}
 	*(p++) = ':';
 	append_str( p, vport.s, vport.len);
+	append_fix( p, ";branch=z9hG4bK");
+	int2bstr(
+		(long)(rand()/(float)RAND_MAX * (MAX_BRANCHID-MIN_BRANCHID) + MIN_BRANCHID),
+		p+LEN_BRANCHID-INT2STR_MAX_LEN+1, NULL);
+	p += LEN_BRANCHID;
 	if (path->len) {
-		append_fix( p, ";branch=0"CRLF"Route: ");
+		append_fix( p, CRLF"Route: ");
 		append_str( p, path->s, path->len);
-		append_fix( p, CRLF"From: ");
-	} else {
-		append_fix( p, ";branch=0"CRLF"From: ");
 	}
+	append_fix( p, CRLF"From: ");
 	append_str( p, sipping_from.s, sipping_from.len);
 	append_fix( p, ";tag=");
 	append_str( p, ruid->s, ruid->len);