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pcap-file: Add support for Linux SLL formatted PCAP files.

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Someone sent me one of these and OVS couldn't read it.  This fixes the
problem.

Reviewed-by: Yifeng Sun <pkusunyifeng@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
This commit is contained in:
Ben Pfaff
2018-11-11 15:41:08 -08:00
parent 308a079ea9
commit 597177a283
1 changed files with 54 additions and 0 deletions
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54
lib/pcap-file.c
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@@ -39,9 +39,15 @@ enum ts_resolution {
PCAP_NSEC,
};
enum network_type {
PCAP_ETHERNET = 0,
PCAP_LINUX_SLL = 0x71
};
struct pcap_file {
FILE *file;
enum ts_resolution resolution;
enum network_type network;
};
struct pcap_hdr {
@@ -130,10 +136,13 @@ ovs_pcap_read_header(struct pcap_file *p_file)
VLOG_WARN("failed to read pcap header: %s", ovs_retval_to_string(error));
return error;
}
bool byte_swap;
if (ph.magic_number == 0xa1b2c3d4 || ph.magic_number == 0xd4c3b2a1) {
byte_swap = ph.magic_number == 0xd4c3b2a1;
p_file->resolution = PCAP_USEC;
} else if (ph.magic_number == 0xa1b23c4d ||
ph.magic_number == 0x4d3cb2a1) {
byte_swap = ph.magic_number == 0x4d3cb2a1;
p_file->resolution = PCAP_NSEC;
} else {
VLOG_WARN("bad magic 0x%08"PRIx32" reading pcap file "
@@ -141,6 +150,13 @@ ovs_pcap_read_header(struct pcap_file *p_file)
"or 0x4d3cb2a1)", ph.magic_number);
return EPROTO;
}
p_file->network = byte_swap ? uint32_byteswap(ph.network) : ph.network;
if (p_file->network != PCAP_ETHERNET &&
p_file->network != PCAP_LINUX_SLL) {
VLOG_WARN("unknown network type %"PRIu16" reading pcap file",
p_file->network);
return EPROTO;
}
return 0;
}
@@ -218,6 +234,44 @@ ovs_pcap_read(struct pcap_file *p_file, struct dp_packet **bufp,
dp_packet_delete(buf);
return error;
}
if (p_file->network == PCAP_LINUX_SLL) {
/* This format doesn't include the destination Ethernet address, which
* is weird. */
struct sll_header {
ovs_be16 packet_type;
ovs_be16 arp_hrd;
ovs_be16 lla_len;
struct eth_addr dl_src;
ovs_be16 reserved;
ovs_be16 protocol;
};
const struct sll_header *sll;
if (len < sizeof *sll) {
VLOG_WARN("pcap packet too short for SLL header");
dp_packet_delete(buf);
return EPROTO;
}
/* Pull Linux SLL header. */
sll = dp_packet_pull(buf, sizeof *sll);
if (sll->lla_len != htons(6)) {
ovs_hex_dump(stdout, sll, sizeof *sll, 0, false);
VLOG_WARN("bad SLL header");
dp_packet_delete(buf);
return EPROTO;
}
/* Push Ethernet header. */
struct eth_header eth = {
/* eth_dst is all zeros because the format doesn't include it. */
.eth_src = sll->dl_src,
.eth_type = sll->protocol,
};
dp_packet_push(buf, &eth, sizeof eth);
}
*bufp = buf;
return 0;
}