kamailio/modules/rtpproxy/rtpproxy_funcs.c

/*
 * $Id$
 *
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * History:
 * --------
 *  2003-11-06  body len is computed using the message len (it's
 *               not taken any more from the msg. content-length) (andrei)
 *  2008-08-30  body len is taken from Conent-length header as it is more 
 *               reliable (UDP packages may contain garbage at the end)(bogdan)
 */

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include "rtpproxy_funcs.h"
#include "../../dprint.h"
#include "../../config.h"
#include "../../ut.h"
#include "../../forward.h"
#include "../../resolve.h"
#include "../../globals.h"
#include "../../udp_server.h"
#include "../../pt.h"
#include "../../parser/msg_parser.h"
#include "../../trim.h"
#include "../../parser/parse_from.h"
#include "../../parser/contact/parse_contact.h"
#include "../../parser/parse_uri.h"
#include "../../parser/parse_content.h"
#include "../../parser/parser_f.h"
#include "../../parser/sdp/sdp_helpr_funcs.h"

#define READ(val) \
	(*(val + 0) + (*(val + 1) << 8) + (*(val + 2) << 16) + (*(val + 3) << 24))
#define advance(_ptr,_n,_str,_error) \
	do{\
		if ((_ptr)+(_n)>(_str).s+(_str).len)\
			goto _error;\
		(_ptr) = (_ptr) + (_n);\
	}while(0);
#define one_of_16( _x , _t ) \
	(_x==_t[0]||_x==_t[15]||_x==_t[8]||_x==_t[2]||_x==_t[3]||_x==_t[4]\
	||_x==_t[5]||_x==_t[6]||_x==_t[7]||_x==_t[1]||_x==_t[9]||_x==_t[10]\
	||_x==_t[11]||_x==_t[12]||_x==_t[13]||_x==_t[14])
#define one_of_8( _x , _t ) \
	(_x==_t[0]||_x==_t[7]||_x==_t[1]||_x==_t[2]||_x==_t[3]||_x==_t[4]\
	||_x==_t[5]||_x==_t[6])



/**
 * return:
 * -1: error
 *  1: text or sdp
 *  2: multipart
 */
int check_content_type(struct sip_msg *msg)
{
	static unsigned int appl[16] = {
		0x6c707061/*appl*/,0x6c707041/*Appl*/,0x6c705061/*aPpl*/,
		0x6c705041/*APpl*/,0x6c507061/*apPl*/,0x6c507041/*ApPl*/,
		0x6c505061/*aPPl*/,0x6c505041/*APPl*/,0x4c707061/*appL*/,
		0x4c707041/*AppL*/,0x4c705061/*aPpL*/,0x4c705041/*APpL*/,
		0x4c507061/*apPL*/,0x4c507041/*ApPL*/,0x4c505061/*aPPL*/,
		0x4c505041/*APPL*/};
	static unsigned int icat[16] = {
		0x74616369/*icat*/,0x74616349/*Icat*/,0x74614369/*iCat*/,
		0x74614349/*ICat*/,0x74416369/*icAt*/,0x74416349/*IcAt*/,
		0x74414369/*iCAt*/,0x74414349/*ICAt*/,0x54616369/*icaT*/,
		0x54616349/*IcaT*/,0x54614369/*iCaT*/,0x54614349/*ICaT*/,
		0x54416369/*icAT*/,0x54416349/*IcAT*/,0x54414369/*iCAT*/,
		0x54414349/*ICAT*/};
	static unsigned int ion_[8] = {
		0x006e6f69/*ion_*/,0x006e6f49/*Ion_*/,0x006e4f69/*iOn_*/,
		0x006e4f49/*IOn_*/,0x004e6f69/*ioN_*/,0x004e6f49/*IoN_*/,
		0x004e4f69/*iON_*/,0x004e4f49/*ION_*/};
	static unsigned int sdp_[8] = {
		0x00706473/*sdp_*/,0x00706453/*Sdp_*/,0x00704473/*sDp_*/,
		0x00704453/*SDp_*/,0x00506473/*sdP_*/,0x00506453/*SdP_*/,
		0x00504473/*sDP_*/,0x00504453/*SDP_*/};
	str           str_type;
	unsigned int  x;
	char          *p;

	if (!msg->content_type)
	{
		LM_WARN("the header Content-TYPE is absent!"
			"let's assume the content is text/plain ;-)\n");
		return 1;
	}

	trim_len(str_type.len,str_type.s,msg->content_type->body);
	if (str_type.len>=15 && (*str_type.s=='m' || *str_type.s=='M')
			&& strncasecmp(str_type.s, "multipart/mixed", 15) == 0) {
		return 2;
    }
	p = str_type.s;
	advance(p,4,str_type,error_1);
	x = READ(p-4);
	if (!one_of_16(x,appl))
		goto other;
	advance(p,4,str_type,error_1);
	x = READ(p-4);
	if (!one_of_16(x,icat))
		goto other;
	advance(p,3,str_type,error_1);
	x = READ(p-3) & 0x00ffffff;
	if (!one_of_8(x,ion_))
		goto other;

	/* skip spaces and tabs if any */
	while (*p==' ' || *p=='\t')
		advance(p,1,str_type,error_1);
	if (*p!='/')
	{
		LM_ERR("no / found after primary type\n");
		goto error;
	}
	advance(p,1,str_type,error_1);
	while ((*p==' ' || *p=='\t') && p+1<str_type.s+str_type.len)
		advance(p,1,str_type,error_1);

	advance(p,3,str_type,error_1);
	x = READ(p-3) & 0x00ffffff;
	if (!one_of_8(x,sdp_))
		goto other;

	if (*p==';'||*p==' '||*p=='\t'||*p=='\n'||*p=='\r'||*p==0) {
		LM_DBG("type <%.*s> found valid\n", (int)(p-str_type.s), str_type.s);
		return 1;
	} else {
		LM_ERR("bad end for type!\n");
		return -1;
	}

error_1:
	LM_ERR("body ended :-(!\n");
error:
	return -1;
other:
	LM_ERR("invalid type for a message\n");
	return -1;
}


/*
 * Get message body and check Content-Type header field
 */
int extract_body(struct sip_msg *msg, str *body )
{
	char c;
	int skip;
	int ret;
	str mpdel;
	char *rest, *p1, *p2;
	struct hdr_field hf;
	unsigned int mime;
	
	body->s = get_body(msg);
	if (body->s==0) {
		LM_ERR("failed to get the message body\n");
		goto error;
	}
	
	/*
	 * Better use the content-len value - no need of any explicit
	 * parcing as get_body() parsed all headers and Conten-Length
	 * body header is automaticaly parsed when found.
	 */
	if (msg->content_length==0) {
		LM_ERR("failed to get the content length in message\n");
		goto error;
	}

	body->len = get_content_length(msg);
	if (body->len==0) {
		LM_ERR("message body has length zero\n");
		goto error;
	}

	if (body->len + body->s > msg->buf + msg->len) {
		LM_ERR("content-length exceeds packet-length by %d\n",
				(int)((body->len + body->s) - (msg->buf + msg->len)));
		goto error;
	}

	/* no need for parse_headers(msg, EOH), get_body will 
	 * parse everything */
	/*is the content type correct?*/
	if((ret = check_content_type(msg))==-1)
	{
		LM_ERR("content type mismatching\n");
		goto error;
	}

	if(ret!=2)
		goto done;

	/* multipart body */
	if(get_mixed_part_delimiter(&msg->content_type->body,&mpdel) < 0) {
		goto error;
	}
	p1 = find_sdp_line_delimiter(body->s, body->s+body->len, mpdel);
	if (p1 == NULL) {
		LM_ERR("empty multipart content\n");
		return -1;
	}
	p2=p1;
	c = 0;
	for(;;)
	{
		p1 = p2;
		if (p1 == NULL || p1 >= body->s+body->len)
			break; /* No parts left */
		p2 = find_next_sdp_line_delimiter(p1, body->s+body->len,
				mpdel, body->s+body->len);
		/* p2 is text limit for application parsing */
		rest = eat_line(p1 + mpdel.len + 2, p2 - p1 - mpdel.len - 2);
		if ( rest > p2 ) {
			LM_ERR("Unparsable <%.*s>\n", (int)(p1-p1), p1);
			return -1;
		}
		while( rest<p2 ) {
			memset(&hf,0, sizeof(struct hdr_field));
			rest = get_sdp_hdr_field(rest, p2, &hf);
			if(hf.type==HDR_EOH_T)
				break;
			if(hf.type==HDR_ERROR_T)
				return -1;
			if(hf.type==HDR_CONTENTTYPE_T) {
				if(decode_mime_type(hf.body.s, hf.body.s + hf.body.len,
						&mime)==NULL)
					return -1;
				if (((((unsigned int)mime)>>16) == TYPE_APPLICATION)
						&& ((mime&0x00ff) == SUBTYPE_SDP)) {
					c = 1;
				}
			}
		} /* end of while */
		if(c==1)
		{
			body->s = rest;
			body->len = p2-rest;
			goto done;
		}
	}

error:
	return -1;

done:
	for (skip = 0; skip < body->len; skip++) {
		c = body->s[body->len - skip - 1];
		if (c != '\r' && c != '\n')
			break;
	}
	if (skip == body->len) {
		LM_ERR("empty body");
		goto error;
	}
	body->len -= skip;

	/*LM_DBG("DEBUG:extract_body:=|%.*s|\n",body->len,body->s);*/
	return 1;
}

/*
 * 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.
 */
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 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)
 */
int
get_callid(struct sip_msg* _m, str* _cid)
{

        if ((parse_headers(_m, HDR_CALLID_F, 0) == -1)) {
                LM_ERR("failed to parse call-id header\n");
                return -1;
        }

        if (_m->callid == NULL) {
                LM_ERR("call-id not found\n");
                return -1;
        }

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

/*
 * 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
 */
int
get_to_tag(struct sip_msg* _m, str* _tag)
{

        if (!_m->to) {
                LM_ERR("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->s = NULL; /* fixes gcc 4.0 warnings */
                _tag->len = 0;
        }

        return 0;
}

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

        if (parse_from_header(_m)<0) {
                LM_ERR("failed to parse 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->s = NULL; /* fixes gcc 4.0 warnings */
                _tag->len = 0;
        }

        return 0;
}

/*
 * Extract URI from the Contact header field
 */
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) {
                LM_ERR("failed to parse 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) {
                LM_ERR("failed to parse Contact URI [%.*s]\n",
                        (*_c)->uri.len, ((*_c)->uri.s)?(*_c)->uri.s:"");
                return -1;
        }
        return 0;
}

/*
 * Extract branch from Via header
 */
int
get_via_branch(struct sip_msg* msg, int vianum, str* _branch)
{
	struct via_body *via;
	struct via_param *p;

	if (parse_via_header(msg, vianum, &via) < 0)
		return -1;

	for (p = via->param_lst; p; p = p->next)
	{
		if (p->name.len == strlen("branch")
				&& strncasecmp(p->name.s, "branch", strlen("branch")) == 0) {
			_branch->s = p->value.s;
			_branch->len = p->value.len;
			return 0;
		}
	}
	return -1;
}