nat_helper.h File Reference

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Detailed Description

Proxy-CSCF - NAT helper for signalling.

Note:

Taken from SER nathelper module

Author:

adapted for the pcscf module by Marius Corici mco -at- fokus dot fraunhofer dot de

Definition in file nat_helper.h.

#include "registrar_storage.h"

Go to the source code of this file.

Data Structures
struct	network_t
	Network structure. More...
Defines
#define	NAT_UAC_TEST_C_1918   0x01
	NAT test for Contact.
#define	NAT_UAC_TEST_RCVD   0x02
	NAT test for received from.
#define	NAT_UAC_TEST_V_1918   0x04
	NAT test for Via.
#define	NAT_UAC_TEST_S_1918   0x08
	NAT test for SDP?
#define	NAT_UAC_TEST_RPORT   0x10
	NAT test for rport.
Functions
char *	ser_memmem (const void *b1, const void *b2, size_t len1, size_t len2)
	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.
int	is1918addr (str *saddr)
	Test if IP address pointed to by saddr belongs to RFC1918 networks.
int	nat_send_ping (r_contact *c)
	Pings a contact to keep the NAT pinhole alive.
int	nat_uac_test (struct sip_msg *msg)
	Tests if the message was received from behind a NAT.
int	nat_prepare_1918addr ()
	Fixes the 1918 private networks addresses.
r_nat_dest *	nat_msg_origin (struct sip_msg *msg)
	Retrieves the originating source of a message into a r_nat_dest structure.
int	requires_nat (struct sip_msg *msg)
	Finds if a NAT pinhole would be required to reach this user.

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Define Documentation

#define NAT_UAC_TEST_C_1918   0x01

NAT test for Contact.

Definition at line 102 of file nat_helper.h.

#define NAT_UAC_TEST_RCVD   0x02

NAT test for received from.

Definition at line 104 of file nat_helper.h.

Referenced by nat_uac_test().

#define NAT_UAC_TEST_V_1918   0x04

NAT test for Via.

Definition at line 106 of file nat_helper.h.

Referenced by nat_uac_test().

#define NAT_UAC_TEST_S_1918   0x08

NAT test for SDP?

Definition at line 108 of file nat_helper.h.

#define NAT_UAC_TEST_RPORT   0x10

NAT test for rport.

Definition at line 110 of file nat_helper.h.

Referenced by nat_uac_test().

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Function Documentation

char* ser_memmem	(	const void *	b1,
		const void *	b2,
		size_t	len1,
		size_t	len2
	)

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.

Definition at line 309 of file nat_helper.c.

References NULL.

Referenced by extract_mediaip(), extract_mediaport(), find_sdp_line(), and force_rtp_proxy2_f().

{
    /* 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;
}

int is1918addr

(

str *

saddr

)

Test if IP address pointed to by saddr belongs to RFC1918 networks.

Parameters:

saddr

- string with address to check

Returns:

if the network is private one

Definition at line 278 of file nat_helper.c.

References network_t::cnetaddr, nets_1918, and NULL.

Referenced by via_1918().

                           {
    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 is1918addr_end;
    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 is1918addr_end;
        }
    }
    rval = 0;

is1918addr_end:
    saddr->s[saddr->len] = backup;
    return rval;
}

int nat_send_ping

(

r_contact *

c

)

Pings a contact to keep the NAT pinhole alive.

Parameters:

c

- the r_contact to ping

Returns:

1 on success, -1 on failure

Definition at line 469 of file nat_helper.c.

References M_NAME, _r_nat_dest::nat_addr, _r_nat_dest::nat_port, NULL, _r_contact::pinhole, _r_contact::transport, and udp_ping.

                                {
    struct dest_info dst;
    
    if(c->pinhole == NULL)
        return 1;
    if(c->transport != PROTO_UDP && c->transport != PROTO_NONE)
        return 1;
    init_dest_info(&dst);
    dst.proto = PROTO_UDP;
    
    memset(&(dst.to), 0, sizeof(union sockaddr_union));
    dst.to.s.sa_family=c->pinhole->nat_addr.af;
    switch(dst.to.s.sa_family) {
        case AF_INET6:
            memcpy(&dst.to.sin6.sin6_addr, c->pinhole->nat_addr.u.addr, c->pinhole->nat_addr.len);
            //dst.to.sin6.sin6_len=sizeof(struct sockaddr_in6);
            dst.to.sin6.sin6_port=htons(c->pinhole->nat_port);
            break;
        case AF_INET:
            memcpy(&dst.to.sin.sin_addr, c->pinhole->nat_addr.u.addr, c->pinhole->nat_addr.len);
            //dst.to.sin.sin_len=sizeof(struct sockaddr_in);
            dst.to.sin.sin_port=htons(c->pinhole->nat_port);
            break;
        default:
            LOG(L_CRIT,"CRIT:"M_NAME":nat_send_ping: unknown address family %d\n", dst.to.s.sa_family);
            return -1;
    }
    dst.send_sock=get_send_socket(0, &dst.to, PROTO_UDP);
    if(dst.send_sock == NULL) {
        LOG(L_ERR,"ERR:"M_NAME":nat_send_ping: cannot get sending socket\n");
        return -1;
    }
    udp_send(&dst, (char *)udp_ping, sizeof(udp_ping));
    return 1; 
}

int nat_uac_test

(

struct sip_msg *

msg

)

Tests if the message was received from behind a NAT.

• tests received, contact and via

  Parameters:

  msg

  - the SIP message

Definition at line 408 of file nat_helper.c.

References NAT_UAC_TEST_RCVD, NAT_UAC_TEST_RPORT, NAT_UAC_TEST_V_1918, pcscf_nat_detection_type, pcscf_nat_pingall, and via_1918().

Referenced by nat_msg_origin(), and requires_nat().

                                       {

    if(pcscf_nat_pingall)
        return 1;
        
    if((pcscf_nat_detection_type && NAT_UAC_TEST_RPORT) && 
        (msg->rcv.src_port != (msg-> via1->port ? msg->via1->port:SIP_PORT)))
        return 1;
    
    if((pcscf_nat_detection_type & NAT_UAC_TEST_RCVD) && received_test(msg))
        return 1;
    
//  if((pcscf_nat_detection_type & NAT_UAC_TEST_C_1918) && contact_1918(msg))
        //return 1;
    
//  if((pcscf_nat_detection_type & NAT_UAC_TEST_S_1918) && sdp_1918(msg))
//      return 1;
        
    if((pcscf_nat_detection_type & NAT_UAC_TEST_V_1918) && via_1918(msg))
        return 1;
    
    return 0;
}

int nat_prepare_1918addr

(

)

Fixes the 1918 private networks addresses.

Definition at line 338 of file nat_helper.c.

References network_t::cnetaddr, network_t::mask, network_t::netaddr, nets_1918, and NULL.

Referenced by mod_init().

                           {
    int i;
    struct in_addr addr;
    
    /* Prepare 1918 networks list */
    for (i = 0; nets_1918[i].cnetaddr != NULL; i++) {
        if (inet_aton(nets_1918[i].cnetaddr, &addr) != 1)
            abort();
        nets_1918[i].netaddr = ntohl(addr.s_addr) & nets_1918[i].mask;
    }
    return 1;
}

r_nat_dest* nat_msg_origin

(

struct sip_msg *

msg

)

Retrieves the originating source of a message into a r_nat_dest structure.

Parameters:

	msg	- the SIP message
	pinhole	- where to save to

Returns:

1 on success, -1 on error

Definition at line 438 of file nat_helper.c.

References M_NAME, _r_nat_dest::nat_addr, nat_uac_test(), NULL, pcscf_nat_enable, and pcscf_nat_pingall.

Referenced by update_contacts().

                                                 {
    r_nat_dest *pinhole=NULL;
    if (!pcscf_nat_enable) return NULL;
    if(pcscf_nat_pingall || nat_uac_test(msg)) {
        pinhole = shm_malloc(sizeof(r_nat_dest));
        if (pinhole == NULL) {
            LOG(L_ERR,"ERR:"M_NAME":nat_msg_origin:no memory\n");
            return NULL;
        }
        memcpy(&pinhole->nat_addr, &msg->rcv.src_ip, sizeof(struct ip_addr));
        pinhole -> nat_port = msg -> rcv.src_port;
    }
    return pinhole;
}

int requires_nat

(

struct sip_msg *

msg

)

Finds if a NAT pinhole would be required to reach this user.

Parameters:

msg

- the SIP message

Returns:

1 if yes, 0 if not

Definition at line 458 of file nat_helper.c.

References nat_uac_test(), pcscf_nat_enable, and pcscf_nat_pingall.

Referenced by P_save_location().

{
    return pcscf_nat_enable && (pcscf_nat_pingall || nat_uac_test(msg));
}

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