X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Flibsystemd-network%2Fdhcp-packet.c;h=7581daeeeb355ae4c53b46fca85e77b2dd837abd;hb=4ec3cd7391e119b597375c547cf4ed50fce9f115;hp=102ed096aff666be3668813973587ab725f5efbc;hpb=0c79c68d93d721d37ba088fb50dbf07bb0d447e5;p=elogind.git diff --git a/src/libsystemd-network/dhcp-packet.c b/src/libsystemd-network/dhcp-packet.c index 102ed096a..7581daeee 100644 --- a/src/libsystemd-network/dhcp-packet.c +++ b/src/libsystemd-network/dhcp-packet.c @@ -38,42 +38,57 @@ #define DHCP_CLIENT_MIN_OPTIONS_SIZE 312 int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid, - uint8_t type, uint8_t **opt, size_t *optlen) { - int err; + uint8_t type, uint16_t arp_type, size_t optlen, + size_t *optoffset) { + size_t offset = 0; + int r; assert(op == BOOTREQUEST || op == BOOTREPLY); + assert(arp_type == ARPHRD_ETHER || arp_type == ARPHRD_INFINIBAND); message->op = op; - message->htype = ARPHRD_ETHER; - message->hlen = ETHER_ADDR_LEN; + message->htype = arp_type; + message->hlen = (arp_type == ARPHRD_ETHER) ? ETHER_ADDR_LEN : 0; message->xid = htobe32(xid); message->magic = htobe32(DHCP_MAGIC_COOKIE); - *opt = (uint8_t *)(message + 1); + r = dhcp_option_append(message, optlen, &offset, 0, + DHCP_OPTION_MESSAGE_TYPE, 1, &type); + if (r < 0) + return r; - err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1, - &type); - if (err < 0) - return err; + *optoffset = offset; return 0; } -uint16_t dhcp_packet_checksum(void *buf, int len) { - uint32_t sum; - uint16_t *check; - int i; - uint8_t *odd; +uint16_t dhcp_packet_checksum(uint8_t *buf, size_t len) { + uint64_t *buf_64 = (uint64_t*)buf; + uint64_t *end_64 = buf_64 + (len / sizeof(uint64_t)); + uint64_t sum = 0; - sum = 0; - check = buf; + /* See RFC1071 */ - for (i = 0; i < len / 2 ; i++) - sum += check[i]; + while (buf_64 < end_64) { + sum += *buf_64; + if (sum < *buf_64) + /* wrap around in one's complement */ + sum++; - if (len & 0x01) { - odd = buf; - sum += odd[len - 1]; + buf_64 ++; + } + + if (len % sizeof(uint64_t)) { + /* If the buffer is not aligned to 64-bit, we need + to zero-pad the last few bytes and add them in */ + uint64_t buf_tail = 0; + + memcpy(&buf_tail, buf_64, len % sizeof(uint64_t)); + + sum += buf_tail; + if (sum < buf_tail) + /* wrap around */ + sum++; } while (sum >> 16) @@ -89,6 +104,8 @@ void dhcp_packet_append_ip_headers(DHCPPacket *packet, be32_t source_addr, packet->ip.ihl = DHCP_IP_SIZE / 4; packet->ip.tot_len = htobe16(len); + packet->ip.tos = IPTOS_CLASS_CS6; + packet->ip.protocol = IPPROTO_UDP; packet->ip.saddr = source_addr; packet->ip.daddr = destination_addr; @@ -99,11 +116,11 @@ void dhcp_packet_append_ip_headers(DHCPPacket *packet, be32_t source_addr, packet->udp.len = htobe16(len - DHCP_IP_SIZE); packet->ip.check = packet->udp.len; - packet->udp.check = dhcp_packet_checksum(&packet->ip.ttl, len - 8); + packet->udp.check = dhcp_packet_checksum((uint8_t*)&packet->ip.ttl, len - 8); packet->ip.ttl = IPDEFTTL; packet->ip.check = 0; - packet->ip.check = dhcp_packet_checksum(&packet->ip, DHCP_IP_SIZE); + packet->ip.check = dhcp_packet_checksum((uint8_t*)&packet->ip, DHCP_IP_SIZE); } int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) { @@ -114,48 +131,48 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) { /* IP */ if (packet->ip.version != IPVERSION) { - log_dhcp_client(client, "ignoring packet: not IPv4"); + log_debug("ignoring packet: not IPv4"); return -EINVAL; } if (packet->ip.ihl < 5) { - log_dhcp_client(client, "ignoring packet: IPv4 IHL (%u words) invalid", - packet->ip.ihl); + log_debug("ignoring packet: IPv4 IHL (%u words) invalid", + packet->ip.ihl); return -EINVAL; } hdrlen = packet->ip.ihl * 4; if (hdrlen < 20) { - log_dhcp_client(client, "ignoring packet: IPv4 IHL (%zu bytes) " - "smaller than minimum (20 bytes)", hdrlen); + log_debug("ignoring packet: IPv4 IHL (%zu bytes) " + "smaller than minimum (20 bytes)", hdrlen); return -EINVAL; } if (len < hdrlen) { - log_dhcp_client(client, "ignoring packet: packet (%zu bytes) " - "smaller than expected (%zu) by IP header", len, - hdrlen); + log_debug("ignoring packet: packet (%zu bytes) " + "smaller than expected (%zu) by IP header", len, + hdrlen); return -EINVAL; } /* UDP */ if (packet->ip.protocol != IPPROTO_UDP) { - log_dhcp_client(client, "ignoring packet: not UDP"); + log_debug("ignoring packet: not UDP"); 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, - hdrlen + be16toh(packet->udp.len)); + log_debug("ignoring packet: packet (%zu bytes) " + "smaller than expected (%zu) by UDP header", len, + hdrlen + be16toh(packet->udp.len)); return -EINVAL; } if (be16toh(packet->udp.dest) != DHCP_PORT_CLIENT) { - log_dhcp_client(client, "ignoring packet: to port %u, which " - "is not the DHCP client port (%u)", - be16toh(packet->udp.dest), DHCP_PORT_CLIENT); + log_debug("ignoring packet: to port %u, which " + "is not the DHCP client port (%u)", + be16toh(packet->udp.dest), DHCP_PORT_CLIENT); return -EINVAL; } @@ -163,8 +180,8 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) { if all the other checks have passed */ - if (dhcp_packet_checksum(&packet->ip, hdrlen)) { - log_dhcp_client(client, "ignoring packet: invalid IP checksum"); + if (dhcp_packet_checksum((uint8_t*)&packet->ip, hdrlen)) { + log_debug("ignoring packet: invalid IP checksum"); return -EINVAL; } @@ -172,9 +189,9 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) { packet->ip.check = packet->udp.len; packet->ip.ttl = 0; - if (dhcp_packet_checksum(&packet->ip.ttl, + if (dhcp_packet_checksum((uint8_t*)&packet->ip.ttl, be16toh(packet->udp.len) + 12)) { - log_dhcp_client(client, "ignoring packet: invalid UDP checksum"); + log_debug("ignoring packet: invalid UDP checksum"); return -EINVAL; } }