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sd-lldp: simplify lldp_network_bind_raw_socket() a bit

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Let's constify the filter program, drop a few includes and structure
definitions.
This commit is contained in:
Lennart Poettering
2016-02-20 22:42:29 +01:00
parent 43a6a52efe
commit 358977458b
1 changed files with 14 additions and 20 deletions
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src/libsystemd-network/lldp-network.c
+14 -20
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@@ -22,62 +22,56 @@
#include <netinet/if_ether.h>
#include "fd-util.h"
#include "lldp-internal.h"
#include "lldp-network.h"
#include "lldp-tlv.h"
#include "socket-util.h"
int lldp_network_bind_raw_socket(int ifindex) {
typedef struct LLDPFrame {
struct ethhdr hdr;
uint8_t tlvs[0];
} LLDPFrame;
struct sock_filter filter[] = {
BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(LLDPFrame, hdr.h_dest)), /* A <- 4 bytes of destination MAC */
static const struct sock_filter filter[] = {
BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ethhdr, h_dest)), /* A <- 4 bytes of destination MAC */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0180c200, 1, 0), /* A != 01:80:c2:00 */
BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(LLDPFrame, hdr.h_dest) + 4), /* A <- remaining 2 bytes of destination MAC */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ethhdr, h_dest) + 4), /* A <- remaining 2 bytes of destination MAC */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0000, 3, 0), /* A != 00:00 */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0003, 2, 0), /* A != 00:03 */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x000e, 1, 0), /* A != 00:0e */
BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(LLDPFrame, hdr.h_proto)), /* A <- protocol */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ethhdr, h_proto)), /* A <- protocol */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_LLDP, 1, 0), /* A != ETHERTYPE_LLDP */
BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */
BPF_STMT(BPF_RET + BPF_K, (uint32_t) -1), /* accept packet */
};
struct sock_fprog fprog = {
static const struct sock_fprog fprog = {
.len = ELEMENTSOF(filter),
.filter = filter
.filter = (struct sock_filter*) filter,
};
_cleanup_close_ int s = -1;
union sockaddr_union saddrll = {
.ll.sll_family = AF_PACKET,
.ll.sll_ifindex = ifindex,
};
_cleanup_close_ int fd = -1;
int r;
assert(ifindex > 0);
s = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
if (s < 0)
fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
if (fd < 0)
return -errno;
r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
r = setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
if (r < 0)
return -errno;
r = bind(s, &saddrll.sa, sizeof(saddrll.ll));
r = bind(fd, &saddrll.sa, sizeof(saddrll.ll));
if (r < 0)
return -errno;
r = s;
s = -1;
r = fd;
fd = -1;
return r;
}