pcapparse: also support extracting tcp data

This commit is contained in:
Mark Nauwelaerts 2011-07-14 16:40:14 +02:00
parent 04f0b55609
commit 93af6831e2

View file

@ -20,8 +20,8 @@
/** /**
* SECTION:element-pcapparse * SECTION:element-pcapparse
* *
* Extracts payloads from Ethernet-encapsulated IP packets, currently limited * Extracts payloads from Ethernet-encapsulated IP packets.
* to UDP. Use #GstPcapParse:src-ip, #GstPcapParse:dst-ip, * Use #GstPcapParse:src-ip, #GstPcapParse:dst-ip,
* #GstPcapParse:src-port and #GstPcapParse:dst-port to restrict which packets * #GstPcapParse:src-port and #GstPcapParse:dst-port to restrict which packets
* should be included. * should be included.
* *
@ -324,6 +324,8 @@ gst_pcap_parse_read_uint32 (GstPcapParse * self, const guint8 * p)
#define UDP_HEADER_LEN 8 #define UDP_HEADER_LEN 8
#define IP_PROTO_UDP 17 #define IP_PROTO_UDP 17
#define IP_PROTO_TCP 6
static gboolean static gboolean
gst_pcap_parse_scan_frame (GstPcapParse * self, gst_pcap_parse_scan_frame (GstPcapParse * self,
@ -331,16 +333,16 @@ gst_pcap_parse_scan_frame (GstPcapParse * self,
gint buf_size, const guint8 ** payload, gint * payload_size) gint buf_size, const guint8 ** payload, gint * payload_size)
{ {
const guint8 *buf_ip = 0; const guint8 *buf_ip = 0;
const guint8 *buf_udp; const guint8 *buf_proto;
guint16 eth_type; guint16 eth_type;
guint8 b; guint8 b;
guint8 ip_header_size; guint8 ip_header_size;
guint8 ip_protocol; guint8 ip_protocol;
guint32 ip_src_addr; guint32 ip_src_addr;
guint32 ip_dst_addr; guint32 ip_dst_addr;
guint16 udp_src_port; guint16 src_port;
guint16 udp_dst_port; guint16 dst_port;
guint16 udp_len; guint16 len;
switch (self->linktype) { switch (self->linktype) {
case DLT_ETHER: case DLT_ETHER:
@ -375,34 +377,53 @@ gst_pcap_parse_scan_frame (GstPcapParse * self,
return FALSE; return FALSE;
ip_protocol = *(buf_ip + 9); ip_protocol = *(buf_ip + 9);
if (ip_protocol != IP_PROTO_UDP) GST_LOG_OBJECT (self, "ip proto %d", (gint) ip_protocol);
if (ip_protocol != IP_PROTO_UDP && ip_protocol != IP_PROTO_TCP)
return FALSE; return FALSE;
/* ip info */
ip_src_addr = *((guint32 *) (buf_ip + 12)); ip_src_addr = *((guint32 *) (buf_ip + 12));
ip_dst_addr = *((guint32 *) (buf_ip + 16));
buf_proto = buf_ip + ip_header_size;
/* ok for tcp and udp */
src_port = GUINT16_FROM_BE (*((guint16 *) (buf_proto + 0)));
dst_port = GUINT16_FROM_BE (*((guint16 *) (buf_proto + 2)));
/* extract some params and data according to protocol */
if (ip_protocol == IP_PROTO_UDP) {
len = GUINT16_FROM_BE (*((guint16 *) (buf_proto + 4)));
if (len < UDP_HEADER_LEN || buf_proto + len > buf + buf_size)
return FALSE;
*payload = buf_proto + UDP_HEADER_LEN;
*payload_size = len - UDP_HEADER_LEN;
} else {
if (buf_proto + 12 >= buf + buf_size)
return FALSE;
len = (buf_proto[12] >> 4) * 4;
if (buf_proto + len > buf + buf_size)
return FALSE;
/* all remaining data following tcp header is payload */
*payload = buf_proto + len;
*payload_size = self->cur_packet_size - (buf_proto - buf) - len;
}
/* but still filter as configured */
if (self->src_ip >= 0 && ip_src_addr != self->src_ip) if (self->src_ip >= 0 && ip_src_addr != self->src_ip)
return FALSE; return FALSE;
ip_dst_addr = *((guint32 *) (buf_ip + 16));
if (self->dst_ip >= 0 && ip_dst_addr != self->dst_ip) if (self->dst_ip >= 0 && ip_dst_addr != self->dst_ip)
return FALSE; return FALSE;
buf_udp = buf_ip + ip_header_size; if (self->src_port >= 0 && src_port != self->src_port)
udp_src_port = GUINT16_FROM_BE (*((guint16 *) (buf_udp + 0)));
if (self->src_port >= 0 && udp_src_port != self->src_port)
return FALSE; return FALSE;
udp_dst_port = GUINT16_FROM_BE (*((guint16 *) (buf_udp + 2))); if (self->dst_port >= 0 && dst_port != self->dst_port)
if (self->dst_port >= 0 && udp_dst_port != self->dst_port)
return FALSE; return FALSE;
udp_len = GUINT16_FROM_BE (*((guint16 *) (buf_udp + 4)));
if (udp_len < UDP_HEADER_LEN || buf_udp + udp_len > buf + buf_size)
return FALSE;
*payload = buf_udp + UDP_HEADER_LEN;
*payload_size = udp_len - UDP_HEADER_LEN;
return TRUE; return TRUE;
} }