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ipv4ll: use BPF on raw socket

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This should significantly reduce spurious wakeups.
This commit is contained in:
Tom Gundersen 2014-04-07 09:17:53 +02:00
parent 463b73e24e
commit 298f77c60c
1 changed files with 27 additions and 0 deletions
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27
src/libsystemd-network/ipv4ll-network.c
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@ -17,6 +17,8 @@
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <linux/filter.h>
#include "util.h"
#include "ipv4ll-internal.h"
@ -33,6 +35,27 @@ int arp_network_send_raw_socket(int fd, const union sockaddr_union *link,
}
int arp_network_bind_raw_socket(int index, union sockaddr_union *link) {
struct sock_filter filter[] = {
BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */
BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(struct ether_arp), 1, 0), /* packet >= arp packet ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_hrd)), /* A <- header */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header == ethernet ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_pro)), /* A <- protocol */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 1, 0), /* protocol == IP ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_op)), /* A <- operation */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 0, 1), /* protocol == request ? */
BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1), /* protocol == reply ? */
BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
};
struct sock_fprog fprog = {
.len = ELEMENTSOF(filter),
.filter = filter
};
int s;
assert(index > 0);
@ -42,6 +65,10 @@ int arp_network_bind_raw_socket(int index, union sockaddr_union *link) {
if (s < 0)
return -errno;
if (setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)) < 0) {
return -errno;
}
link->ll.sll_family = AF_PACKET;
link->ll.sll_protocol = htons(ETH_P_ARP);
link->ll.sll_ifindex = index;