chan_sip.c

/*
 * Asterisk -- A telephony toolkit for Linux.
 *
 * Implementation of Session Initiation Protocol
 * 
 * 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
 */

#include <stdio.h>
#include <ctype.h>
#include <pthread.h>
#include <string.h>
#include <asterisk/lock.h>
#include <asterisk/channel.h>
#include <asterisk/channel_pvt.h>
#include <asterisk/config.h>
#include <asterisk/logger.h>
#include <asterisk/module.h>
#include <asterisk/pbx.h>
#include <asterisk/options.h>
#include <asterisk/lock.h>
#include <asterisk/sched.h>
#include <asterisk/io.h>
#include <asterisk/rtp.h>
#include <asterisk/acl.h>
#include <asterisk/callerid.h>
#include <asterisk/cli.h>
#include <asterisk/md5.h>
#include <asterisk/app.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/signal.h>
#include <netinet/ip.h>

/* #define VOCAL_DATA_HACK */

#define SIPDUMPER
#define DEFAULT_EXPIREY 120
#define MAX_EXPIREY     3600
#define DEFAULT_MAXMS		2000		/* Must be faster than 2 seconds by default */

#define DEFAULT_MAXMS		2000		/* Must be faster than 2 seconds by default */
#define DEFAULT_FREQ_OK		60 * 1000		/* How often to check for the host to be up */
#define DEFAULT_FREQ_NOTOK	10 * 1000		/* How often to check, if the host is down... */

static char *desc = "Session Initiation Protocol (SIP)";
static char *type = "sip";
static char *tdesc = "Session Initiation Protocol (SIP)";
static char *config = "sip.conf";

#define DEFAULT_SIP_PORT	5060	/* From RFC 2543 */
#define SIP_MAX_PACKET	1500		/* Also from RFC 2543, should sub headers tho */

static char context[AST_MAX_EXTENSION] = "default";

static char language[MAX_LANGUAGE] = "";

static int usecnt =0;
static pthread_mutex_t usecnt_lock = AST_MUTEX_INITIALIZER;

/* Protect the interface list (of sip_pvt's) */
static pthread_mutex_t iflock = AST_MUTEX_INITIALIZER;

/* Protect the monitoring thread, so only one process can kill or start it, and not
   when it's doing something critical. */
static pthread_mutex_t netlock = AST_MUTEX_INITIALIZER;

static pthread_mutex_t monlock = AST_MUTEX_INITIALIZER;

/* This is the thread for the monitor which checks for input on the channels
   which are not currently in use.  */
static pthread_t monitor_thread = 0;

static int restart_monitor(void);

/* Just about everybody seems to support ulaw, so make it a nice default */
static int capability = AST_FORMAT_ULAW | AST_FORMAT_ALAW | AST_FORMAT_GSM;

static char ourhost[256];
static struct in_addr __ourip;
static int ourport;

static int sipdebug = 0;

static int tos = 0;

/* Expire slowly */
static int expirey = 900;

static struct sched_context *sched;
static struct io_context *io;
/* The private structures of the  sip channels are linked for
   selecting outgoing channels */
   
#define SIP_MAX_HEADERS		64
#define SIP_MAX_LINES 		64

struct sip_request {
  char *rlPart1; /* SIP Method Name or "SIP/2.0" protocol version */
  char *rlPart2; /* The Request URI or Response Status */
	int len;
	int headers;					/* SIP Headers */
	char *header[SIP_MAX_HEADERS];
	int lines;						/* SDP Content */
	char *line[SIP_MAX_LINES];
	char data[SIP_MAX_PACKET];
};

static struct sip_pvt {
	pthread_mutex_t lock;				/* Channel private lock */
	char callid[80];					/* Global CallID */
	char randdata[80];	/* Random data */
	unsigned int ocseq;					/* Current outgoing seqno */
	unsigned int icseq;					/* Current incoming seqno */
	int lastinvite;						/* Last Cseq of invite */
	int alreadygone;					/* Whether or not we've already been destroyed by or peer */
	int needdestroy;					/* if we need to be destroyed */
	int capability;						/* Special capability */
	int outgoing;						/* Outgoing or incoming call? */
	int insecure;						/* Don't check source port/ip */
	int expirey;						/* How long we take to expire */
	int branch;							/* One random number */
	int canreinvite;					/* Do we support reinvite */
	int progress;						/* Have sent 183 message progress */
	int tag;							/* Another random number */
	struct sockaddr_in sa;				/* Our peer */
	struct in_addr ourip;				/* Our IP */
	struct ast_channel *owner;			/* Who owns us */
	char exten[AST_MAX_EXTENSION];		/* Extention where to start */
	char refer_to[AST_MAX_EXTENSION];	/* Place to store REFER-TO extension */
	char referred_by[AST_MAX_EXTENSION];/* Place to store REFERRED-BY extension */
	char refer_contact[AST_MAX_EXTENSION];/* Place to store Contact info from a REFER extension */
	char record_route[256];
	char record_route_info[256];
	char remote_party_id[256];
	char context[AST_MAX_EXTENSION];
	char language[MAX_LANGUAGE];
	char theirtag[256];				/* Their tag */
	char username[81];
	char peername[81];
	char peersecret[81];
	char callerid[256];					/* Caller*ID */
	char via[256];
	char accountcode[256];				/* Account code */
	int amaflags;						/* AMA Flags */
	struct sip_request initreq;			/* Initial request */
	
	int maxtime;						/* Max time for first response */
	int initid;							/* Auto-congest ID if appropriate */
	
	struct sip_peer *peerpoke;			/* If this calls is to poke a peer, which one */
	struct sip_registry *registry;			/* If this is a REGISTER call, to which registry */
	struct ast_rtp *rtp;				/* RTP Session */
	struct sip_pvt *next;
} *iflist = NULL;

static struct sip_pkt {
	int retrans;
	struct sip_pvt *owner;
	int packetlen;
	char data[SIP_MAX_PACKET];
	struct sip_pkt *next;
} *packets = NULL;	

struct sip_user {
	/* Users who can access various contexts */
	char name[80];
	char secret[80];
	char context[80];
	char callerid[80];
	char methods[80];
	char accountcode[80];
	int hascallerid;
	int amaflags;
	int insecure;
	int canreinvite;
	struct ast_ha *ha;
	struct sip_user *next;
};

struct sip_peer {
	char name[80];
	char secret[80];
	char context[80];		/* JK02: peers need context too to allow parking etc */
	char methods[80];
	char username[80];
	char mailbox[AST_MAX_EXTENSION];
	int lastmsgssent;
	time_t	lastmsgcheck;
	int dynamic;
	int expire;
	int expirey;
	int capability;
	int insecure;
	int canreinvite;
	struct sockaddr_in addr;
	struct in_addr mask;

	/* Qualification */
	struct sip_pvt *call;		/* Call pointer */
	int pokeexpire;				/* When to expire poke */
	int lastms;					/* How long last response took (in ms), or -1 for no response */
	int maxms;					/* Max ms we will accept for the host to be up, 0 to not monitor */
	struct timeval ps;			/* Ping send time */
	
	struct sockaddr_in defaddr;
	struct ast_ha *ha;
	int delme;
	int lastmsg;
	struct sip_peer *next;
};

static struct ast_user_list {
	struct sip_user *users;
	pthread_mutex_t lock;
} userl = { NULL, AST_MUTEX_INITIALIZER };

static struct ast_peer_list {
	struct sip_peer *peers;
	pthread_mutex_t lock;
} peerl = { NULL, AST_MUTEX_INITIALIZER };


#define REG_STATE_UNREGISTERED 0
#define REG_STATE_REGSENT	   1
#define REG_STATE_AUTHSENT 	   2
#define REG_STATE_REGISTERED   3
#define REG_STATE_REJECTED	   4
#define REG_STATE_TIMEOUT	   5
#define REG_STATE_NOAUTH	   6

struct sip_registry {
	pthread_mutex_t lock;				/* Channel private lock */
	struct sockaddr_in addr;		/* Who we connect to for registration purposes */
	char username[80];
	char secret[80];			/* Password or key name in []'s */
	char random[80];
	int expire;					/* Sched ID of expiration */
	int timeout; 					/* sched id of sip_reg_timeout */
	int refresh;					/* How often to refresh */
	struct sip_pvt *call;				/* create a sip_pvt structure for each outbound "registration call" in progress */
	int regstate;
	int callid_valid;		/* 0 means we haven't chosen callid for this registry yet. */
	char callid[80];		/* Global CallID for this registry */
	struct sockaddr_in us;			/* Who the server thinks we are */
	struct sip_registry *next;
};

static int sip_do_register(struct sip_registry *r);
struct sip_registry *registrations;

static int sipsock  = -1;

static struct sockaddr_in bindaddr;

static struct ast_frame  *sip_read(struct ast_channel *ast);
static int transmit_response(struct sip_pvt *p, char *msg, struct sip_request *req);
static int transmit_response_with_sdp(struct sip_pvt *p, char *msg, struct sip_request *req);
static int transmit_response_with_auth(struct sip_pvt *p, char *msg, struct sip_request *req, char *rand);
static int transmit_request(struct sip_pvt *p, char *msg, int inc);
static int transmit_invite(struct sip_pvt *p, char *msg, int sendsdp, char *auth, char *vxml_url);
static int transmit_reinvite_with_sdp(struct sip_pvt *p, struct ast_rtp *rtp);
static int transmit_message_with_text(struct sip_pvt *p, char *text);
static int do_proxy_auth(struct sip_pvt *p, struct sip_request *req);

static int __sip_xmit(struct sip_pvt *p, char *data, int len)
{
	int res;
    res=sendto(sipsock, data, len, 0, (struct sockaddr *)&p->sa, sizeof(struct sockaddr_in));
	if (res != len) {
		ast_log(LOG_WARNING, "sip_xmit of %p (len %d) to %s returned %d: %s\n", data, len, inet_ntoa(p->sa.sin_addr), res, strerror(errno));
	}
	return res;
}

static int send_response(struct sip_pvt *p, struct sip_request *req)
{
	int res;
	if (sipdebug)
		ast_verbose("Transmitting:\n%s\n to %s:%d\n", req->data, inet_ntoa(p->sa.sin_addr), ntohs(p->sa.sin_port));
	res = __sip_xmit(p, req->data, req->len);
	if (res > 0)
		res = 0;
	return res;
}

static int send_request(struct sip_pvt *p, struct sip_request *req)
{
	int res;
	if (sipdebug)
		ast_verbose("XXX Need to handle Retransmitting XXX:\n%s to %s:%d\n", req->data, inet_ntoa(p->sa.sin_addr), ntohs(p->sa.sin_port));
	res = __sip_xmit(p, req->data, req->len);
	return res;
}

static char *ditch_braces(char *tmp)
{
	char *c = tmp;
	char *n;
	c = tmp;
	if ((n = strchr(tmp, '<')) ) {
		c = n + 1;
		while(*c && *c != '>') c++;
		if (*c != '>') {
			ast_log(LOG_WARNING, "No closing brace in '%s'\n", tmp);
		} else {
			*c = '\0';
		}
		return n+1;
	}
	return c;
}

static int sip_sendtext(struct ast_channel *ast, char *text)
{
	struct sip_pvt *p = ast->pvt->pvt;
	if (sipdebug) 
		ast_verbose("Sending text %s on %s\n", text, ast->name);
	if (!p)
		return -1;
	if (!text || !strlen(text))
		return 0;
	if (sipdebug)
		ast_verbose("Really sending text %s on %s\n", text, ast->name);
	transmit_message_with_text(p, text);
	return 0;	
}

static int create_addr(struct sip_pvt *r, char *peer)
{
	struct hostent *hp;
	struct sip_peer *p;
	int found=0;
	r->sa.sin_family = AF_INET;
	ast_pthread_mutex_lock(&peerl.lock);
	p = peerl.peers;
	while(p) {
		if (!strcasecmp(p->name, peer)) {
			found++;
			r->capability = p->capability;
			strncpy(r->peername, p->username, sizeof(r->peername)-1);
			strncpy(r->peersecret, p->secret, sizeof(r->peersecret)-1);
			strncpy(r->username, p->username, sizeof(r->username)-1);
			r->insecure = p->insecure;
			r->canreinvite = p->canreinvite;
			r->maxtime = p->maxms;
			strncpy(r->context, p->context,sizeof(r->context)-1);
			if ((p->addr.sin_addr.s_addr || p->defaddr.sin_addr.s_addr) &&
				(!p->maxms || ((p->lastms > 0)  && (p->lastms <= p->maxms)))) {
				if (p->addr.sin_addr.s_addr) {
					r->sa.sin_addr = p->addr.sin_addr;
					r->sa.sin_port = p->addr.sin_port;
				} else {
					r->sa.sin_addr = p->defaddr.sin_addr;
					r->sa.sin_port = p->defaddr.sin_port;
				}
				break;
			}
		}
		p = p->next;
	}
	ast_pthread_mutex_unlock(&peerl.lock);
	if (!p && !found) {
		hp = gethostbyname(peer);
		if (hp) {
			memcpy(&r->sa.sin_addr, hp->h_addr, sizeof(r->sa.sin_addr));
			r->sa.sin_port = htons(DEFAULT_SIP_PORT);
			return 0;
		} else {
			ast_log(LOG_WARNING, "No such host: %s\n", peer);
			return -1;
		}
	} else if (!p)
		return -1;
	else
		return 0;
}

static int auto_congest(void *nothing)
{
	struct sip_pvt *p = nothing;
	ast_pthread_mutex_lock(&p->lock);
	p->initid = -1;
	if (p->owner) {
		if (!pthread_mutex_trylock(&p->owner->lock)) {
			ast_log(LOG_NOTICE, "Auto-congesting %s\n", p->owner->name);
			ast_queue_control(p->owner, AST_CONTROL_CONGESTION, 0);
			ast_pthread_mutex_unlock(&p->owner->lock);
		}
	}
	ast_pthread_mutex_unlock(&p->lock);
	return 0;
}

static int sip_call(struct ast_channel *ast, char *dest, int timeout)
{
	int res;
	struct sip_pvt *p;
	char *vxml_url = NULL;
	struct varshead *headp;
	struct ast_var_t *current;
	
	p = ast->pvt->pvt;
	if ((ast->_state != AST_STATE_DOWN) && (ast->_state != AST_STATE_RESERVED)) {
		ast_log(LOG_WARNING, "sip_call called on %s, neither down nor reserved\n", ast->name);
		return -1;
	}

	/* Check whether there is a VXML_URL variable */
	headp=&ast->varshead;
	AST_LIST_TRAVERSE(headp,current,entries) {
		if (strcasecmp(ast_var_name(current),"VXML_URL")==0)
	        {
			vxml_url = ast_var_value(current);
			break;
		}
	}
	
	res = 0;
	p->outgoing = 1;
	transmit_invite(p, "INVITE", 1, NULL, vxml_url);
	if (p->maxtime) {
		/* Initialize auto-congest time */
		p->initid = ast_sched_add(sched, p->maxtime * 2, auto_congest, p);
	}
	return res;
}

static void __sip_destroy(struct sip_pvt *p, int lockowner)
{
	struct sip_pvt *cur, *prev = NULL;
	if (p->rtp) {
		ast_rtp_destroy(p->rtp);
	}
	/* Unlink us from the owner if we have one */
	if (p->owner) {
		if (lockowner)
			ast_pthread_mutex_lock(&p->owner->lock);
		ast_log(LOG_DEBUG, "Detaching from %s\n", p->owner->name);
		p->owner->pvt->pvt = NULL;
		if (lockowner)
			ast_pthread_mutex_unlock(&p->owner->lock);
	}
	cur = iflist;
	while(cur) {
		if (cur == p) {
			if (prev)
				prev->next = cur->next;
			else
				iflist = cur->next;
			break;
		}
		prev = cur;
		cur = cur->next;
	}
	if (!cur) {
		ast_log(LOG_WARNING, "%p is not in list?!?! \n", cur);
	} else {
		if (p->initid > -1)
			ast_sched_del(sched, p->initid);
		free(p);
	}
}
static void sip_destroy(struct sip_pvt *p)
{
	ast_pthread_mutex_lock(&iflock);
	__sip_destroy(p, 1);
	ast_pthread_mutex_unlock(&iflock);
}

/* Interface lookup code courtesy Tilghman of DrunkCoder.com.  Thanks! */

struct my_ifreq {
    union
      {
	char ifrn_name[IFNAMSIZ];	/* Interface name, e.g. "en0".  */
      } ifr_ifrn;

    union
      {
	struct sockaddr_in ifru_addr;
	char ifru_data[512];
      } ifr_ifru;
};

struct in_addr *lookup_iface(char *iface) {
	int mysock;
	int res;
	static struct  my_ifreq ifreq;
	memset(&ifreq, 0, sizeof(ifreq));
	strncpy(ifreq.ifr_ifrn.ifrn_name,iface,sizeof(ifreq.ifr_ifrn.ifrn_name) - 1);

	mysock = socket(PF_INET,SOCK_DGRAM,IPPROTO_IP);
	res = ioctl(mysock,SIOCGIFADDR,&ifreq);
	
	close(mysock);
	if (res < 0) {
		ast_log(LOG_WARNING, "Unable to get IP of %s: %s\n", iface, strerror(errno));
		return &__ourip;
	}
	return( (struct in_addr *) &ifreq.ifr_ifru.ifru_addr.sin_addr );
}

static struct in_addr *myaddrfor(struct in_addr *them)
{
	FILE *PROC;
	struct in_addr *temp = NULL;
	unsigned int remote_ip;
	char line[256];
	remote_ip = them->s_addr;
	
	PROC = fopen("/proc/net/route","r");
	if (!PROC) {
		/* If /proc/net/route doesn't exist, fall back to the old method */
		return &__ourip;
	}
	/* First line contains headers */
	fgets(line,sizeof(line),PROC);

	while (!feof(PROC)) {
		char iface[8];
		unsigned int dest, gateway, mask;
		int i,aoffset;
		char *fields[40];

		fgets(line,sizeof(line),PROC);

		aoffset = 0;
		for (i=0;i<sizeof(line);i++) {
			char *boffset;

			fields[aoffset++] = line + i;
			boffset = strchr(line + i,'\t');
			if (boffset == NULL) {
				/* Exit loop */
				break;
			} else {
				*boffset = '\0';
				i = boffset - line;
			}
		}

		sscanf(fields[0],"%s",iface);
		sscanf(fields[1],"%x",&dest);
		sscanf(fields[2],"%x",&gateway);
		sscanf(fields[7],"%x",&mask);
#if 0
		printf("Addr: %s %08x Dest: %08x Mask: %08x\n", inet_ntoa(*them), remote_ip, dest, mask);
#endif		
		if (((remote_ip & mask) ^ dest) == 0) {
			if (sipdebug)
				ast_verbose("Interface is %s\n",iface);
			temp = lookup_iface(iface);
			if (sipdebug)
				ast_verbose("IP Address is %s\n",inet_ntoa(*temp));
			break;
		}
	}
	fclose(PROC);
	if (!temp) {
		ast_log(LOG_WARNING, "Couldn't figure out how to get to %s.  Using default\n", inet_ntoa(*them));
 		temp = &__ourip;
 	}
	return temp;
}


static int sip_hangup(struct ast_channel *ast)
{
	struct sip_pvt *p = ast->pvt->pvt;
	int needcancel = 0;
	if (option_debug)
		ast_log(LOG_DEBUG, "sip_hangup(%s)\n", ast->name);
	if (!ast->pvt->pvt) {
		ast_log(LOG_DEBUG, "Asked to hangup channel not connected\n");
		return 0;
	}
	ast_pthread_mutex_lock(&p->lock);
	/* Determine how to disconnect */
	if (p->owner != ast) {
		ast_log(LOG_WARNING, "Huh?  We aren't the owner?\n");
		ast_pthread_mutex_unlock(&p->lock);
		return 0;
	}
	if (!ast || (ast->_state != AST_STATE_UP))
		needcancel = 1;
	/* Disconnect */
	p = ast->pvt->pvt;
	p->owner = NULL;
	ast->pvt->pvt = NULL;

	p->needdestroy = 1;
#if 0
	/* Invert sense of outgoing */
	p->outgoing = 1 - p->outgoing;
#endif	
	/* Start the process if it's not already started */
	if (!p->alreadygone && strlen(p->initreq.data)) {
		if (needcancel) {
			transmit_request(p, "CANCEL", 0);
		} else {
			/* Send a hangup */
			transmit_request(p, "BYE", p->outgoing);
		}
	}
#if 0
	/* Restore sense of outgoing */
	p->outgoing = 1 - p->outgoing;
#endif	
	ast_pthread_mutex_unlock(&p->lock);
	return 0;
}

static int sip_answer(struct ast_channel *ast)
{
	int res = 0;
	struct sip_pvt *p = ast->pvt->pvt;
	if (ast->_state != AST_STATE_UP) {
		ast_setstate(ast, AST_STATE_UP);
		if (option_debug)
			ast_log(LOG_DEBUG, "sip_answer(%s)\n", ast->name);
		res = transmit_response_with_sdp(p, "200 OK", &p->initreq);
	}
	return res;
}

static int sip_write(struct ast_channel *ast, struct ast_frame *frame)
{
	struct sip_pvt *p = ast->pvt->pvt;
	int res = 0;
	if (frame->frametype != AST_FRAME_VOICE) {
		if (frame->frametype == AST_FRAME_IMAGE)
			return 0;
		else {
			ast_log(LOG_WARNING, "Can't send %d type frames with SIP write\n", frame->frametype);
			return 0;
		}
	} else {
		if (!(frame->subclass & ast->nativeformats)) {
			ast_log(LOG_WARNING, "Asked to transmit frame type %d, while native formats is %d (read/write = %d/%d)\n",
				frame->subclass, ast->nativeformats, ast->readformat, ast->writeformat);
			return -1;
		}
	}
	if (p) {
		ast_pthread_mutex_lock(&p->lock);
		if (p->rtp) {
			if ((ast->_state != AST_STATE_UP) && !p->progress && !p->outgoing) {
				transmit_response_with_sdp(p, "183 Session Progress", &p->initreq);
				p->progress = 1;
			}
			res =  ast_rtp_write(p->rtp, frame);
		}
		ast_pthread_mutex_unlock(&p->lock);
	}
	return res;
}

static int sip_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
{
	struct sip_pvt *p = newchan->pvt->pvt;
	ast_pthread_mutex_lock(&p->lock);
	if (p->owner != oldchan) {
		ast_log(LOG_WARNING, "old channel wasn't %p but was %p\n", oldchan, p->owner);
		ast_pthread_mutex_unlock(&p->lock);
		return -1;
	}
	p->owner = newchan;
	ast_pthread_mutex_unlock(&p->lock);
	return 0;
}

static int sip_senddigit(struct ast_channel *ast, char digit)
{
	struct sip_pvt *p = ast->pvt->pvt;
	if (p && p->rtp) {
		ast_rtp_senddigit(p->rtp, digit);
		return 0;
	}
	return -1;
}

static int sip_indicate(struct ast_channel *ast, int condition)
{
	struct sip_pvt *p = ast->pvt->pvt;
	switch(condition) {
	case AST_CONTROL_RINGING:
		if (ast->_state == AST_STATE_RING) {
			transmit_response(p, "180 Ringing", &p->initreq);
			break;
		}
		return -1;
	case AST_CONTROL_BUSY:
		if (ast->_state != AST_STATE_UP) {
			transmit_response(p, "600 Busy everywhere", &p->initreq);
			p->alreadygone = 1;
			ast_softhangup(ast, AST_SOFTHANGUP_DEV);
			break;
		}
		return -1;
	case AST_CONTROL_CONGESTION:
		if (ast->_state != AST_STATE_UP) {
			transmit_response(p, "486 Busy here", &p->initreq);
			p->alreadygone = 1;
			ast_softhangup(ast, AST_SOFTHANGUP_DEV);
			break;
		}
		return -1;
	case -1:
		return -1;
	default:
		ast_log(LOG_WARNING, "Don't know how to indicate condition %d\n", condition);
		return -1;
	}
	return 0;
}


static int sip_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc)
{
	struct sip_pvt *p0, *p1;
	struct ast_frame *f;
	struct ast_channel *who, *cs[3];
	int to;

	/* if need DTMF, cant native bridge */
	if (flags & (AST_BRIDGE_DTMF_CHANNEL_0 | AST_BRIDGE_DTMF_CHANNEL_1))
		return -2;
	ast_pthread_mutex_lock(&c0->lock);
	ast_pthread_mutex_lock(&c1->lock);
	p0 = c0->pvt->pvt;
	p1 = c1->pvt->pvt;
	if (!p0->canreinvite || !p1->canreinvite) {
		/* Not gonna support reinvite */
		ast_pthread_mutex_unlock(&c0->lock);
		ast_pthread_mutex_unlock(&c1->lock);
		return -2;
	}
	transmit_reinvite_with_sdp(p0, p1->rtp);
	transmit_reinvite_with_sdp(p1, p0->rtp);
	ast_pthread_mutex_unlock(&c0->lock);
	ast_pthread_mutex_unlock(&c1->lock);
	cs[0] = c0;
	cs[1] = c1;
	cs[2] = NULL;
	for (;;) {
		if ((c0->pvt->pvt != p0)  ||
			(c1->pvt->pvt != p1) ||
			(c0->masq || c0->masqr || c1->masq || c1->masqr)) {
				ast_log(LOG_DEBUG, "Oooh, something is weird, backing out\n");
				if (c0->pvt->pvt == p0)
					transmit_reinvite_with_sdp(p0, NULL);
				if (c1->pvt->pvt == p1)
					transmit_reinvite_with_sdp(p1, NULL);
				/* Tell it to try again later */
				return -3;
		}
		to = -1;
		who = ast_waitfor_n(cs, 2, &to);
		if (!who) {
			ast_log(LOG_DEBUG, "Ooh, empty read...\n");
			continue;
		}
		f = ast_read(who);
		if (!f || ((f->frametype == AST_FRAME_DTMF) &&
				   (((who == c0) && (flags & AST_BRIDGE_DTMF_CHANNEL_0)) || 
			       ((who == c1) && (flags & AST_BRIDGE_DTMF_CHANNEL_1))))) {
			*fo = f;
			*rc = who;
			ast_log(LOG_DEBUG, "Oooh, got a %s\n", f ? "digit" : "hangup");
			if (c0->pvt->pvt == p0 && !c0->_softhangup)
				transmit_reinvite_with_sdp(p0, NULL);
			if (c1->pvt->pvt == p1 && !c1->_softhangup)
				transmit_reinvite_with_sdp(p1, NULL);
			/* That's all we needed */
			return 0;
		} else 
			ast_frfree(f);
		/* Swap priority not that it's a big deal at this point */
		cs[2] = cs[0];
		cs[0] = cs[1];
		cs[1] = cs[2];
		
	}
	return -1;
}

static struct ast_channel *sip_new(struct sip_pvt *i, int state, char *title)
{
	struct ast_channel *tmp;
	int fmt;
	tmp = ast_channel_alloc(1);
	if (tmp) {
		tmp->nativeformats = i->capability;
		if (!tmp->nativeformats)
			tmp->nativeformats = capability;
		fmt = ast_best_codec(tmp->nativeformats);
		if (title)
			snprintf(tmp->name, sizeof(tmp->name), "SIP/%s", title);
		else
			snprintf(tmp->name, sizeof(tmp->name), "SIP/%s:%d", inet_ntoa(i->sa.sin_addr), ntohs(i->sa.sin_port));
		tmp->type = type;
		tmp->fds[0] = ast_rtp_fd(i->rtp);
		ast_setstate(tmp, state);
		if (state == AST_STATE_RING)
			tmp->rings = 1;
		tmp->writeformat = fmt;
		tmp->pvt->rawwriteformat = fmt;
		tmp->readformat = fmt;
		tmp->pvt->rawreadformat = fmt;
		tmp->pvt->pvt = i;
		tmp->pvt->send_text = sip_sendtext;
		tmp->pvt->call = sip_call;
		tmp->pvt->hangup = sip_hangup;
		tmp->pvt->answer = sip_answer;
		tmp->pvt->read = sip_read;
		tmp->pvt->write = sip_write;
		tmp->pvt->indicate = sip_indicate;
		tmp->pvt->fixup = sip_fixup;
		tmp->pvt->send_digit = sip_senddigit;
		tmp->pvt->bridge = sip_bridge;
		if (strlen(i->language))
			strncpy(tmp->language, i->language, sizeof(tmp->language)-1);
		i->owner = tmp;
		ast_pthread_mutex_lock(&usecnt_lock);
		usecnt++;
		ast_pthread_mutex_unlock(&usecnt_lock);
		ast_update_use_count();
		strncpy(tmp->context, i->context, sizeof(tmp->context)-1);
		strncpy(tmp->exten, i->exten, sizeof(tmp->exten)-1);
		if (strlen(i->callerid))
			tmp->callerid = strdup(i->callerid);
		tmp->priority = 1;
		if (state != AST_STATE_DOWN) {
			if (ast_pbx_start(tmp)) {
				ast_log(LOG_WARNING, "Unable to start PBX on %s\n", tmp->name);
				ast_hangup(tmp);
				tmp = NULL;
			}
		}
	} else
		ast_log(LOG_WARNING, "Unable to allocate channel structure\n");
	return tmp;
}

static struct cfalias {
	char *fullname;
	char *shortname;
} aliases[] = {
	{ "Content-Type", "c" },
	{ "Content-Encoding", "e" },
	{ "From", "f" },
	{ "Call-ID", "i" },
	{ "Contact", "m" },
	{ "Content-Length", "l" },
	{ "Subject", "s" },
	{ "To", "t" },
	{ "Via", "v" },
};

static char *get_sdp(struct sip_request *req, char *name)
{
	int x;
	int len = strlen(name);
	char *r;
	for (x=0;x<req->lines;x++) {
		if (!strncasecmp(req->line[x], name, len) && 
				(req->line[x][len] == '=')) {
					r = req->line[x] + len + 1;
					while(*r && (*r < 33))
							r++;
					return r;
		}
	}
	return "";
}

static char *__get_header(struct sip_request *req, char *name, int *start)
{
	int x;
	int len = strlen(name);
	char *r;
	for (x=*start;x<req->headers;x++) {
		if (!strncasecmp(req->header[x], name, len) && 
				(req->header[x][len] == ':')) {
					r = req->header[x] + len + 1;
					while(*r && (*r < 33))
							r++;
					*start = x+1;
					return r;
		}
	}
	/* Try aliases */
	for (x=0;x<sizeof(aliases) / sizeof(aliases[0]); x++) 
		if (!strcasecmp(aliases[x].fullname, name))
			return __get_header(req, aliases[x].shortname, start);

	/* Don't return NULL, so get_header is always a valid pointer */
	return "";
}

static char *get_header(struct sip_request *req, char *name)
{
	int start = 0;
	return __get_header(req, name, &start);
}

static struct ast_frame *sip_rtp_read(struct sip_pvt *p)
{
	/* Retrieve audio/etc from channel.  Assumes p->lock is already held. */
	struct ast_frame *f;
	f = ast_rtp_read(p->rtp);
	if (p->owner) {
		/* We already hold the channel lock */
		if (f->frametype == AST_FRAME_VOICE) {
			if (f->subclass != p->owner->nativeformats) {
				ast_log(LOG_DEBUG, "Oooh, format changed to %d\n", f->subclass);
				p->owner->nativeformats = f->subclass;
				ast_set_read_format(p->owner, p->owner->readformat);
				ast_set_write_format(p->owner, p->owner->writeformat);
			}
		}
	}
	return f;
}

static struct ast_frame *sip_read(struct ast_channel *ast)
{
	struct ast_frame *fr;
	struct sip_pvt *p = ast->pvt->pvt;
	ast_pthread_mutex_lock(&p->lock);
	fr = sip_rtp_read(p);
	ast_pthread_mutex_unlock(&p->lock);
	return fr;
}

static void build_callid(char *callid, int len, struct in_addr ourip)
{
	int res;
	int val;
	int x;
	for (x=0;x<4;x++) {
		val = rand();
		res = snprintf(callid, len, "%08x", val);
		len -= res;
		callid += res;
	}
	/* It's not important that we really use our right IP here... */
	snprintf(callid, len, "@%s", inet_ntoa(ourip));
}

static struct sip_pvt *sip_alloc(char *callid, struct sockaddr_in *sin)
{
	struct sip_pvt *p;

	p = malloc(sizeof(struct sip_pvt));
	if (!p)
		return NULL;
	/* Keep track of stuff */
	memset(p, 0, sizeof(struct sip_pvt));
	p->initid = -1;
	p->rtp = ast_rtp_new(NULL, NULL);
	p->branch = rand();	
	p->tag = rand();
	/* Start with 101 instead of 1 */
	p->ocseq = 101;
	if (!p->rtp) {
		ast_log(LOG_WARNING, "Unable to create RTP session: %s\n", strerror(errno));
		free(p);
		return NULL;
	}
	ast_rtp_settos(p->rtp, tos);
	ast_pthread_mutex_init(&p->lock);
#if 0
	ast_rtp_set_data(p->rtp, p);
	ast_rtp_set_callback(p->rtp, rtpready);
#endif	
	if (sin) {
		memcpy(&p->sa, sin, sizeof(p->sa));
		memcpy(&p->ourip, myaddrfor(&p->sa.sin_addr), sizeof(p->ourip));
	} else {
		memcpy(&p->ourip, &__ourip, sizeof(p->ourip));
	}
	snprintf(p->via, sizeof(p->via), "SIP/2.0/UDP %s:%d;branch=%08x", inet_ntoa(p->ourip), ourport, p->branch);
	if (!callid)
		build_callid(p->callid, sizeof(p->callid), p->ourip);
	else
		strncpy(p->callid, callid, sizeof(p->callid) - 1);