Testing SIP INVITEs -- I think I used this to prank Vonage users w/ATA-186s back in the day

send-invite.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <md5.h>

#define WWW_AUTH	1
#define PROXY_AUTH	2

#define ACK		10
#define	OK		11
#define	CANCEL		12

extern int errno;
extern int h_errno;

char *our_ip, *our_username, *our_realm, *our_passwd, our_host[256], current_method[64];
int our_port, cseq, pktstatus, our_uid;
long callid, tag;

void process_pktstatus(char *incoming, int incominglen)
{
	char tmp[4];
	int i, offset;

	offset = 8;
	i = offset;

	while (((incoming[i] != ' ') && (i != incominglen))) {
		tmp[i - offset] = incoming[i];
		i++;
	}

	tmp[i - offset] = '\0';
	pktstatus = atoi(tmp);
	printf("Got a SIP 2.0 packet with a status code of %d\n\n\n", pktstatus);
}

int process_message(char *incoming, int incominglen)
{
	int i, offset;
	char from[512], to[512], dest[512], msg[2048];
	char *ptr;

	offset = 8;
	i = offset;

	while(((incoming[i] != ' ') && (i != incominglen))) {
		dest[i - offset] = incoming[i];
		i++;
	}
	dest[i - offset] = '\0';

	ptr = strstr(incoming, "From:");
	if (ptr == NULL) {
		printf("Could not find From: in packet\n");
	} else {
		offset = 6;
		i = offset;

		while(((ptr[i] != '\r') && (i != incominglen))) {
			from[i - offset] = ptr[i];
			i++;
		}

		from[i - offset] = '\0';
	}

	ptr = strstr(incoming, "To:");
	if (ptr == NULL) {
		printf("Could not find To: in packet\n");
	} else {
		offset = 4;
		i = offset;

		while(((ptr[i] != '\r') && (i != incominglen))) {
			to[i - offset] = ptr[i];
			i++;
		}

		to[i - offset] = '\0';
	}

	ptr = strstr(incoming, "\r\n\r\n");
	if (ptr == NULL) {
		printf("Could not find start of message in packet\n");
	} else {
		offset = 4;
		i = offset;

		while(i != incominglen && i != (sizeof(msg) - 1)) {
			msg[i - offset] = ptr[i];
			i++;
		}

		msg[i - offset] = '\0';
	}

	if (from && to && dest && msg) {
		printf("Message sent from %s to %s (%s):\n", from, to, dest);
		printf("%s\n", msg);
		return 0;
	} else {
		return -1;
	}
}

int send_pkt(int s, char *pkt, struct sockaddr_in sin)
{
	int len, slen;

	len = strlen(pkt);
	slen = sendto(s, pkt, len, 0, (struct sockaddr *)&sin, sizeof(struct sockaddr));
	if (slen != len) {
		perror("sendto");
		exit(-1);
	}

	printf("Sent %d bytes to %s:%d\n", slen, inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
	printf("%s\n", pkt);

	return(slen);
}

void send_reply(int s, char *incoming, int incominglen, struct sockaddr_in sin, int reply, char *method)
{
	char rcvd_callid[256], *pkt, from[256], *ptr, contact[256], to[256], via[4096], tmp[255], tmp2[8];
	int i, j, k, offset, vias = 0;

	ptr = strstr(incoming, "Via:");
	if (ptr == NULL) {
		printf("Could not find Via: in packet\n");
	} else {
		i = 0;
		j = 0;

		while (i != incominglen) {
			if (ptr[i] == 'V' && ptr[i + 1] == 'i' && ptr[i + 2] == 'a' && ptr[i + 3] == ':') {
				while(ptr[i] != '\r') {
					via[j] = ptr[i];
					i++;
					j++;
				}

				vias++;
				via[j] = '\0';
				if (vias == 1) {
					offset = 17;
					k = offset;

					while((via[k] != ';' && via[k] != ':' && via[k] != '\r') && ((k - offset) < sizeof(tmp))) {
						tmp[k - offset] = via[k];
						k++;
					}

					if (strcmp(tmp, our_host) == 0 && strcmp(tmp, our_ip) == 0) {
						tmp[k - offset] = '\0';
						sin.sin_addr.s_addr = inet_addr(tmp);
						offset = k;

						if (via[k] == ':') {
							k++; offset++;
							while(via[k] != ';' && via[k] != '\r') {
								tmp2[k - offset] = via[k];
								k++;
							}

							sin.sin_port = htons(atoi(tmp2));
						}
					}

					strncat(via, ";received=", sizeof(via));
					strncat(via, our_ip, sizeof(via));
					j += strlen(";received=") + strlen(our_ip);
				}

				via[j] = '\r';
				j++;
				via[j] = '\n';	
				j++;
			}

			i++;
		}

		via[j - 2] = '\0';
	}

	ptr = strstr(incoming, "From:");
	if (ptr == NULL) {
		printf("Could not find From: in packet\n");
	} else {
		offset = 6;
		i = offset;

		while(((ptr[i] != '\r') && (i != incominglen))) {
			from[i - offset] = ptr[i];
			i++;
		}

		from[i - offset] = '\0';
	}

	ptr = strstr(incoming, "To:");
	if (ptr == NULL) {
		printf("Could not find To: in packet\n");
	} else {
		offset = 4;
		i = offset;

		while(((ptr[i] != '\r') && (i != incominglen))) {
			to[i - offset] = ptr[i];
			i++;
		}

		to[i - offset] = '\0';
	}

	ptr = strstr(incoming, "Contact:");
	if (ptr == NULL) {
		printf("Could not find Contact: in packet\n");
	} else {
		offset = 9;
		i = offset;

		while(((ptr[i] != '\r') && (i != incominglen))) {
			contact[i - offset] = ptr[i];
			i++;
		}

		contact[i - offset] = '\0';
	}

	ptr = strstr(incoming, "Call-ID:");
	if (ptr != NULL) {
		offset = 9;
		i = offset;

		while(incoming[i] != '\r' && i != incominglen) {
			rcvd_callid[i - offset] = ptr[i];
			i++;
		}
		rcvd_callid[i - offset] = '\0';
	} else {
		snprintf(rcvd_callid, sizeof(rcvd_callid), "%d@%s", callid, our_host);
	}

	if (from && rcvd_callid) {
		switch(reply) {
			case ACK:
				asprintf(&pkt, "ACK sip:%d@%s SIP/2.0\nVia: SIP/2.0/UDP %s:%d\nFrom: %s\nTo: %s\nContact: %s\nCall-Id: %s\nCSeq: %d %s\n\n", our_uid, our_ip, our_ip, our_port, from, to, contact, rcvd_callid, cseq, method);
				break;
			case OK:
				asprintf(&pkt, "SIP/2.0 200 OK\n%s\nFrom: %s\nTo: %s;tag=%ld\nContact: %d@%s\nCall-Id: %s\nCSeq: %d %s\nContent-Length: 0\n\n", via, from, to, tag, our_uid, our_ip, rcvd_callid, cseq, method);
				break;
			case CANCEL:
				asprintf(&pkt, "CANCEL %s SIP/2.0\nVia: SIP/2.0/UDP %s:%d\nFrom: %s\nTo: %s;tag=%ld\nContact: %d@%s\nCall-Id: %s\nCSeq: %d %s\nContent-Length: 0\n\n", to, our_host, our_port, from, to, tag, our_uid, our_ip, rcvd_callid, cseq, method);
				break;
			default:
				printf("Unknown reply packet specified.\n");
				break;
		}

		if (pkt != NULL) {
			send_pkt(s, pkt, sin);
			free(pkt);
		}
	}
}

void get_current_cseq(char *incoming, int incominglen)
{
	int i, offset;
	char tmp[16], *ptr;

	ptr = strstr(incoming, "CSeq:");
	if (ptr != NULL) {
		offset = 6;
		i = offset;

		while(ptr[i] != ' ' && i != incominglen) {
			tmp[i - offset] = ptr[i];
			i++;
		}

		tmp[i - offset] = '\0';
		cseq = atoi(tmp);

		// printf("Current CSeq is set to %d\n", cseq);
	}
}

int recv_pkt(int s, char *incoming, int incominglen, struct sockaddr_in sin)
{
	int len, rlen;

	len = sizeof(struct sockaddr);
	bzero(incoming, incominglen);
	rlen = recvfrom(s, incoming, incominglen, 0, (struct sockaddr *)&sin, &len);
	if (rlen > 0) {
		printf("Received %d bytes from %s:%d\n", rlen, inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
		printf("%s\n", incoming);
	}

	get_current_cseq(incoming, rlen);

	if (incoming[0] == 'S' && incoming[1] == 'I' && incoming[2] == 'P' && incoming[3] == '/' && incoming[4] == '2' && incoming[5] == '.' && incoming[6] == '0')	{
		process_pktstatus(incoming, rlen);
	} else if (incoming[0] == 'M' && incoming[1] == 'E' && incoming[2] == 'S' && incoming[3] == 'S' && incoming[4] == 'A' && incoming[5] == 'G' && incoming[6] == 'E') {
		if (process_message(incoming, rlen) == 0) {
			strncpy(current_method, "MESSAGE", sizeof(current_method));
			send_reply(s, incoming, rlen, sin, OK, "MESSAGE");
		}
	} else if (incoming[0] == 'B' && incoming[1] == 'Y' && incoming[2] == 'E') {
		strncpy(current_method, "BYE", sizeof(current_method));
		send_reply(s, incoming, rlen, sin, ACK, "BYE");
	}

	return(rlen);
}

int send_register(int s, struct sockaddr_in sin, char *authc, char *authz, char *incoming, int type)
{
	char *ptr, *pkt;
	int i = 0, slen = 0, offset;
	char realm[256], nonce[256];
	char stage1_md5[33], stage2_md5[33], stage3_md5[33], uri[512];
	MD5_CTX ctx;

	ptr = strstr(incoming, authc);
	if (ptr != NULL) {
		ptr = strstr(incoming, "realm");
	
		while(ptr[i] != '"') {
			i++;
		}
	
		i++;
		offset = i;
		while(ptr[i] != '"') {
			realm[i - offset] = ptr[i];
			i++;
		}
		realm[i - offset] = '\0';
	
		i = 0;
		ptr = strstr(incoming, "nonce");

		while(ptr[i] != '"') {
			i++;
		}
	
		i++;
		offset = i;
		while(ptr[i] != '"') {
			nonce[i - offset] = ptr[i];
			i++;
		}
	
		nonce[i - offset] = '\0';

		MD5Init(&ctx);
		MD5Update(&ctx, our_username, strlen(our_username));
		MD5Update(&ctx, ":", 1);
		MD5Update(&ctx, realm, strlen(realm));
		MD5Update(&ctx, ":", 1);
		MD5Update(&ctx, our_passwd, strlen(our_passwd));
		MD5End(&ctx, stage1_md5);

		if (type == PROXY_AUTH)
			snprintf(uri, sizeof(uri), "sip:%s@%s", our_username, our_realm);
		else if (type == WWW_AUTH)
			snprintf(uri, sizeof(uri), "sip:%s", our_realm);
		else
			snprintf(uri, sizeof(uri), "UNKNOWNAUTHMETHOD");

		MD5Init(&ctx);
		MD5Update(&ctx, current_method, strlen(current_method));
		MD5Update(&ctx, ":", 1);
		MD5Update(&ctx, uri, strlen(uri));
		MD5End(&ctx, stage2_md5);
	
		MD5Init(&ctx);
		MD5Update(&ctx, stage1_md5, strlen(stage1_md5));
		MD5Update(&ctx, ":", 1);
		MD5Update(&ctx, nonce, strlen(nonce));
		MD5Update(&ctx, ":", 1);
		MD5Update(&ctx, stage2_md5, strlen(stage2_md5));
		MD5End(&ctx, stage3_md5);

		cseq++;
		asprintf(&pkt, "%s sip:%s SIP/2.0\nVia: SIP/2.0/UDP %s:%d\nFrom: sip:%s@%s\nTo: sip:%s@%s\nContact: sip:%ld@%s\nCall-Id: %ld@%s\nCSeq: %d %s\n%s: DIGEST username=\"%s\", realm=\"%s\", nonce=\"%s\", uri=\"%s\", response=\"%s\"\n\n", current_method, our_realm, our_ip, our_port, our_username, our_realm, our_username, our_realm, our_uid, our_ip, callid, our_host, cseq, current_method, authz, our_username, realm, nonce, uri, stage3_md5);
		if (pkt == NULL) {
			perror("asprintf");
			return(-1);
		}
	
		slen = send_pkt(s, pkt, sin);
		free(pkt);
	}

	return(slen);
}

int main(int argc, char **argv)
{
	struct sockaddr_in isin, osin;
	int s;
	char *pkt, incoming[1024];
	struct hostent *he;

	if (argc != 8) {
		printf("%s <my ip> <my port> <sip server> <sip port> <username> <realm> <password>\n", argv[0]);
		return(-1);
	}

	our_uid = getuid();

	asprintf(&our_ip, argv[1]);
	if (our_ip == NULL) {
		perror("asprintf");
		return(-1);
	}

	our_port = atoi(argv[2]);
	if (our_port <= 0) {
		perror("atoi");
		return(-1);
	}

	asprintf(&our_username, argv[5]);
	if (our_username == NULL) {
		perror("asprintf");
		return(-1);
	}

	asprintf(&our_realm, argv[6]);
	if (our_realm == NULL) {
		perror("asprintf");
		return(-1);
	}

	asprintf(&our_passwd, argv[7]);
	if (our_passwd == NULL) {
		perror("asprintf");
		return(-1);
	}

	s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (s < 0) {
		perror("socket");
		return(-1);
	}

	isin.sin_family = AF_INET;
	isin.sin_addr.s_addr = inet_addr(our_ip);
	isin.sin_port = htons(our_port);

	if (bind(s, (struct sockaddr *)&isin, sizeof(struct sockaddr)) != 0) {
		perror("bind");
		return(-1);
	}

	if (inet_addr(argv[3]) == INADDR_NONE) {
		he = gethostbyname(argv[3]);
		if (he == NULL) {
			herror("gethostbyname");
			return(-1);
		}

		memcpy((char *)&osin.sin_addr.s_addr, he->h_addr_list[0], he->h_length);
	} else {
		osin.sin_addr.s_addr = inet_addr(argv[3]);
	}

	osin.sin_family = AF_INET;
	osin.sin_port = htons(atoi(argv[4]));

	srandomdev();
	cseq = 1;
	callid = random();
	tag = random();

	if (gethostname(our_host, sizeof(our_host)) != 0) {
		perror("gethostname");
		return(-1);
	}

	asprintf(&pkt, "INVITE sip:asterisk@%s;user=phone SIP/2.0\nVia: SIP/2.0/UDP %s:%d\nFrom: sip:%s@%s\nTo: sip:asterisk@%s;user=phone\nContact: sip:%ld@%s\nCall-Id: %ld@%s\nCSeq: %d INVITE\n\n", inet_ntoa(osin.sin_addr), our_ip, our_port, our_username, our_realm, inet_ntoa(osin.sin_addr), our_uid, our_ip, callid, our_host, cseq);
	if (pkt == NULL) {
		perror("asprintf");
		return(-1);
	}

	strncpy(current_method, "INVITE", sizeof(current_method));
	send_pkt(s, pkt, osin);
	free(pkt);

	while(1) {
		recv_pkt(s, incoming, sizeof(incoming), osin);

		switch(pktstatus) {
			case 400:
				send_reply(s, incoming, sizeof(incoming), osin, CANCEL, current_method);
				break;
			case 401:
				send_register(s, osin, "WWW-Authenticate", "Authorization", incoming, WWW_AUTH);
				break;
			case 407:
				send_register(s, osin, "Proxy-Authenticate", "Proxy-Authentication", incoming, PROXY_AUTH);
				break;
			case 200:
				send_reply(s, incoming, sizeof(incoming), osin, ACK, current_method);
				break;
			case 100:
			default:
		}
	}

	close(s);
	free(our_realm);
	free(our_username);
	free(our_passwd);
	free(our_ip);

	return 0;
}

$ ls -la sip/rfc/send-invite.c
-rw-r--r--  1 missnglnk  staff  12292 Aug 13  2003 sip/rfc/send-invite.c