22 Dec
2012
22 Dec
'12
7:02 p.m.
Module: sip-router
Branch: pd/outbound
Commit: 0c3d25f4fba43ee66a6f1edf88b1abfde97668c8
URL:
http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=0c3d25f…
Author: Peter Dunkley <peter.dunkley(a)crocodile-rcs.com>
Committer: Peter Dunkley <peter.dunkley(a)crocodile-rcs.com>
Date: Sat Dec 22 17:02:01 2012 +0000
modules_k/outbound: Improved flow token encode/decode. Now should work properly with IPv4
and IPv6
---
modules_k/outbound/ob_mod.c | 68 ++++++++++++++++++++++++++-----------------
1 files changed, 41 insertions(+), 27 deletions(-)
diff --git a/modules_k/outbound/ob_mod.c b/modules_k/outbound/ob_mod.c
index 63e922f..59c02f3 100644
--- a/modules_k/outbound/ob_mod.c
+++ b/modules_k/outbound/ob_mod.c
@@ -96,20 +96,23 @@ static int mod_init(void)
<HMAC-SHA1-80><protocol><dst_ip><dst_port><src_ip><src_port>
10 + 1 + 16 + 2 + 16 + 2
- = 47 bytes
+ = 47 bytes maximum
- IP addresses will always be 16 bytes. When an IPv4 address is used the
- address will be encoded in the first four bytes and the last four bytes will
- be ignored.
+ <protocol> specifies whether the addresses are IPv4 or IPv6 and the
+ transport.
+ Bits 0-6: transport (see sip_protos enum from ip_addr.h)
+ Bit 7: IPv6 if set, IPv4 if unset
- base64 encoded size: ceiling((47+2)/3)*4 = 68 bytes
+ IP addresses will be 4 (for IPv6) or 16 (for IPv6) bytes.
+
+ Maximum base64 encoded size: ceiling((47+2)/3)*4 = 68 bytes
*/
-#define UNENC_FLOW_TOKEN_LENGTH 47
-#define SHA1_LENGTH 20
-#define SHA1_80_LENGTH 10
-#define FLOW_TOKEN_START_POS (SHA1_80_LENGTH)
-static unsigned char unenc_flow_token[UNENC_FLOW_TOKEN_LENGTH];
+#define UNENC_FLOW_TOKEN_MAX_LENGTH 47
+#define SHA1_LENGTH 20
+#define SHA1_80_LENGTH 10
+#define FLOW_TOKEN_START_POS (SHA1_80_LENGTH)
+static unsigned char unenc_flow_token[UNENC_FLOW_TOKEN_MAX_LENGTH];
static unsigned char hmac_sha1[EVP_MAX_MD_SIZE];
int encode_flow_token(str *flow_token, struct receive_info rcv)
@@ -123,16 +126,17 @@ int encode_flow_token(str *flow_token, struct receive_info rcv)
}
/* Encode protocol information */
- unenc_flow_token[pos++] = rcv.proto;
+ unenc_flow_token[pos++] =
+ (rcv.dst_ip.af == AF_INET6 ? 0x80 : 0x00) | rcv.proto;
/* Encode destination address */
- for (i = 0; i < 16; i++)
+ for (i = 0; i < (rcv.dst_ip.af == AF_INET6 ? 16 : 4); i++)
unenc_flow_token[pos++] = rcv.dst_ip.u.addr[i];
unenc_flow_token[pos++] = (rcv.dst_port >> 8) & 0xff;
unenc_flow_token[pos++] = rcv.dst_port & 0xff;
/* Encode source address */
- for (i = 0; i < 16; i++)
+ for (i = 0; i < (rcv.src_ip.af == AF_INET6 ? 16 : 4); i++)
unenc_flow_token[pos++] = rcv.src_ip.u.addr[i];
unenc_flow_token[pos++] = (rcv.dst_port >> 8) & 0xff;
unenc_flow_token[pos++] = rcv.dst_port & 0xff;
@@ -141,46 +145,46 @@ int encode_flow_token(str *flow_token, struct receive_info rcv)
prepend onto the flow token */
HMAC(EVP_sha1(), ob_key.s, ob_key.len,
&unenc_flow_token[FLOW_TOKEN_START_POS],
- UNENC_FLOW_TOKEN_LENGTH - FLOW_TOKEN_START_POS,
+ pos - FLOW_TOKEN_START_POS,
hmac_sha1, NULL);
memcpy(unenc_flow_token, &hmac_sha1[SHA1_LENGTH - SHA1_80_LENGTH],
SHA1_80_LENGTH);
/* base64 encode the entire flow token and store for the caller to
use */
- flow_token->s = pkg_malloc(base64_enc_len(UNENC_FLOW_TOKEN_LENGTH));
+ flow_token->s = pkg_malloc(base64_enc_len(pos));
if (flow_token->s == NULL)
{
LM_ERR("allocating package memory\n");
return -1;
}
- flow_token->len = base64_enc(unenc_flow_token, UNENC_FLOW_TOKEN_LENGTH,
+ flow_token->len = base64_enc(unenc_flow_token, pos,
(unsigned char *) flow_token->s,
- base64_enc_len(UNENC_FLOW_TOKEN_LENGTH));
+ base64_enc_len(pos));
return 0;
}
int decode_flow_token(struct receive_info *rcv, str flow_token)
{
- int pos = FLOW_TOKEN_START_POS, i;
+ int pos = FLOW_TOKEN_START_POS, flow_length, i;
- if (flow_token.len != base64_enc_len(UNENC_FLOW_TOKEN_LENGTH))
+ if (flow_token.len > base64_enc_len(UNENC_FLOW_TOKEN_MAX_LENGTH))
{
- LM_ERR("bad flow token length. Length is %d, expected %d\n",
- flow_token.len, UNENC_FLOW_TOKEN_LENGTH);
+ LM_ERR("bad flow token length. Length is %d, expected <= %d\n",
+ flow_token.len, UNENC_FLOW_TOKEN_MAX_LENGTH);
return -1;
}
/* base64 decode the flow token */
- base64_dec((unsigned char *) flow_token.s, flow_token.len,
- unenc_flow_token, UNENC_FLOW_TOKEN_LENGTH);
+ flow_length = base64_dec((unsigned char *) flow_token.s, flow_token.len,
+ unenc_flow_token, UNENC_FLOW_TOKEN_MAX_LENGTH);
/* HMAC-SHA1 the flow token (after the hash) and compare with the
truncated hash at the start of the flow token. */
HMAC(EVP_sha1(), ob_key.s, ob_key.len,
&unenc_flow_token[FLOW_TOKEN_START_POS],
- UNENC_FLOW_TOKEN_LENGTH - FLOW_TOKEN_START_POS,
+ flow_length - FLOW_TOKEN_START_POS,
hmac_sha1, NULL);
if (memcmp(unenc_flow_token, &hmac_sha1[SHA1_LENGTH - SHA1_80_LENGTH],
SHA1_80_LENGTH) != 0)
@@ -190,16 +194,26 @@ int decode_flow_token(struct receive_info *rcv, str flow_token)
}
/* Decode protocol information */
- rcv->proto = unenc_flow_token[pos++];
+ if (unenc_flow_token[pos] & 0x80)
+ {
+ rcv->dst_ip.af = rcv->src_ip.af = AF_INET6;
+ rcv->dst_ip.len = rcv->src_ip.len = 16;
+ }
+ else
+ {
+ rcv->dst_ip.af = rcv->src_ip.af = AF_INET;
+ rcv->dst_ip.len = rcv->src_ip.len = 4;
+ }
+ rcv->proto = unenc_flow_token[pos++] & 0x7f;
/* Decode destination address */
- for (i = 0; i < 16; i++)
+ for (i = 0; i < (rcv->dst_ip.af == AF_INET6 ? 16 : 4); i++)
rcv->dst_ip.u.addr[i] = unenc_flow_token[pos++];
rcv->dst_port = ((unenc_flow_token[pos++] << 8) & 0xff)
| (unenc_flow_token[pos++] & 0xff);
/* Decode source address */
- for (i = 0; i < 16; i++)
+ for (i = 0; i < (rcv->src_ip.af == AF_INET6 ? 16 : 4); i++)
rcv->src_ip.u.addr[i] = unenc_flow_token[pos++];
rcv->src_port = ((unenc_flow_token[pos++] << 8) & 0xff)
| (unenc_flow_token[pos++] & 0xff);