int dhcp_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(DHCPPacket), 1, 0), /* packet >= DHCPPacket ? */
+ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */
- BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol = UDP? */
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol == UDP ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)), /* A <- UDP destination port */
- BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_PORT_CLIENT, 1, 0), /* UDP destination port = DHCP client? */
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_PORT_CLIENT, 1, 0), /* UDP destination port == DHCP client port ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
};
/* IP */
- if (len < DHCP_IP_SIZE) {
- log_dhcp_client(client, "ignoring packet: packet (%zu bytes) "
- " smaller than IP header (%u bytes)", len,
- DHCP_IP_SIZE);
- return -EINVAL;
- }
-
if (packet->ip.version != IPVERSION) {
log_dhcp_client(client, "ignoring packet: not IPv4");
return -EINVAL;
return -EINVAL;
}
- if (len < DHCP_IP_UDP_SIZE) {
- log_dhcp_client(client, "ignoring packet: packet (%zu bytes) "
- " smaller than IP+UDP header (%u bytes)", len,
- DHCP_IP_UDP_SIZE);
- return -EINVAL;
- }
-
if (len < hdrlen + be16toh(packet->udp.len)) {
log_dhcp_client(client, "ignoring packet: packet (%zu bytes) "
"smaller than expected (%zu) by UDP header", len,
assert(client->event);
assert(message);
- if (len < DHCP_MESSAGE_SIZE) {
- log_dhcp_client(client, "message too small (%d bytes): "
- "ignoring", len);
- return 0;
- }
-
if (be32toh(message->magic) != DHCP_MAGIC_COOKIE) {
log_dhcp_client(client, "not a DHCP message: ignoring");
return 0;
return -ENOMEM;
len = read(fd, message, buflen);
- if (len < 0)
+ if (len < 0) {
+ log_dhcp_client(client, "could not receive message from UDP "
+ "socket: %s", strerror(errno));
+ return 0;
+ } else if ((size_t)len < sizeof(DHCPMessage))
return 0;
return client_handle_message(client, message, len);
log_dhcp_client(client, "could not receive message from raw "
"socket: %s", strerror(errno));
return 0;
- }
+ } else if ((size_t)len < sizeof(DHCPPacket))
+ return 0;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) {