diff options
Diffstat (limited to 'src/libsystemd-network/ipv4ll-network.c')
| -rw-r--r-- | src/libsystemd-network/ipv4ll-network.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/src/libsystemd-network/ipv4ll-network.c b/src/libsystemd-network/ipv4ll-network.c index 9525408de9..b917fbf3ac 100644 --- a/src/libsystemd-network/ipv4ll-network.c +++ b/src/libsystemd-network/ipv4ll-network.c @@ -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; |