| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| /*** |
| Copyright © 2013 Intel Corporation. All rights reserved. |
| ***/ |
| |
| #include <errno.h> |
| #include <net/ethernet.h> |
| #include <net/if.h> |
| #include <net/if_arp.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <linux/filter.h> |
| #include <linux/if_infiniband.h> |
| #include <linux/if_packet.h> |
| |
| #include "dhcp-internal.h" |
| #include "fd-util.h" |
| #include "socket-util.h" |
| #include "unaligned.h" |
| |
| static int _bind_raw_socket( |
| int ifindex, |
| union sockaddr_union *link, |
| uint32_t xid, |
| const struct hw_addr_data *hw_addr, |
| const struct hw_addr_data *bcast_addr, |
| uint16_t arp_type, |
| uint16_t port, |
| bool so_priority_set, |
| int so_priority) { |
| |
| assert(ifindex > 0); |
| assert(link); |
| assert(hw_addr); |
| assert(bcast_addr); |
| assert(IN_SET(arp_type, ARPHRD_ETHER, ARPHRD_INFINIBAND)); |
| |
| switch (arp_type) { |
| case ARPHRD_ETHER: |
| assert(hw_addr->length == ETH_ALEN); |
| assert(bcast_addr->length == ETH_ALEN); |
| break; |
| case ARPHRD_INFINIBAND: |
| assert(hw_addr->length == 0); |
| assert(bcast_addr->length == INFINIBAND_ALEN); |
| break; |
| default: |
| assert_not_reached(); |
| } |
| |
| 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_STMT(BPF_RET + BPF_K, 0), /* ignore */ |
| BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags */ |
| BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x20), /* A <- A & 0x20 (More Fragments bit) */ |
| BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ |
| BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ |
| BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags + Fragment offset */ |
| BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff (Fragment offset) */ |
| BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ |
| 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, port, 1, 0), /* UDP destination port == DHCP client port ? */ |
| BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ |
| BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.op)), /* A <- DHCP op */ |
| BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, BOOTREPLY, 1, 0), /* op == BOOTREPLY ? */ |
| BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ |
| BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.htype)), /* A <- DHCP header type */ |
| BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, arp_type, 1, 0), /* header type == arp_type ? */ |
| BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ |
| BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.xid)), /* A <- client identifier */ |
| BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, xid, 1, 0), /* client identifier == xid ? */ |
| BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ |
| BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.hlen)), /* A <- MAC address length */ |
| BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, (uint8_t) hw_addr->length, 1, 0), /* address length == hw_addr->length ? */ |
| BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ |
| |
| /* We only support MAC address length to be either 0 or 6 (ETH_ALEN). Optionally |
| * compare chaddr for ETH_ALEN bytes. */ |
| BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETH_ALEN, 0, 8), /* A (the MAC address length) == ETH_ALEN ? */ |
| BPF_STMT(BPF_LDX + BPF_IMM, unaligned_read_be32(hw_addr->bytes)), /* X <- 4 bytes of client's MAC */ |
| BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr)), /* A <- 4 bytes of MAC from dhcp.chaddr */ |
| BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_X, 0, 1, 0), /* A == X ? */ |
| BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ |
| BPF_STMT(BPF_LDX + BPF_IMM, unaligned_read_be16(hw_addr->bytes + 4)), /* X <- remainder of client's MAC */ |
| BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr) + 4), /* A <- remainder of MAC from dhcp.chaddr */ |
| BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_X, 0, 1, 0), /* A == X ? */ |
| BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ |
| |
| BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.magic)), /* A <- DHCP magic cookie */ |
| BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_MAGIC_COOKIE, 1, 0), /* cookie == DHCP magic cookie ? */ |
| BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ |
| BPF_STMT(BPF_RET + BPF_K, UINT32_MAX), /* accept */ |
| }; |
| struct sock_fprog fprog = { |
| .len = ELEMENTSOF(filter), |
| .filter = filter |
| }; |
| _cleanup_close_ int s = -EBADF; |
| int r; |
| |
| s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); |
| if (s < 0) |
| return -errno; |
| |
| r = setsockopt_int(s, SOL_PACKET, PACKET_AUXDATA, true); |
| if (r < 0) |
| return r; |
| |
| r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)); |
| if (r < 0) |
| return -errno; |
| |
| if (so_priority_set) { |
| r = setsockopt_int(s, SOL_SOCKET, SO_PRIORITY, so_priority); |
| if (r < 0) |
| return r; |
| } |
| |
| link->ll = (struct sockaddr_ll) { |
| .sll_family = AF_PACKET, |
| .sll_protocol = htobe16(ETH_P_IP), |
| .sll_ifindex = ifindex, |
| .sll_hatype = htobe16(arp_type), |
| .sll_halen = bcast_addr->length, |
| }; |
| /* We may overflow link->ll. link->ll_buffer ensures we have enough space. */ |
| memcpy(link->ll.sll_addr, bcast_addr->bytes, bcast_addr->length); |
| |
| r = bind(s, &link->sa, SOCKADDR_LL_LEN(link->ll)); |
| if (r < 0) |
| return -errno; |
| |
| return TAKE_FD(s); |
| } |
| |
| int dhcp_network_bind_raw_socket( |
| int ifindex, |
| union sockaddr_union *link, |
| uint32_t xid, |
| const struct hw_addr_data *hw_addr, |
| const struct hw_addr_data *bcast_addr, |
| uint16_t arp_type, |
| uint16_t port, |
| bool so_priority_set, |
| int so_priority) { |
| |
| static struct hw_addr_data default_eth_bcast = { |
| .length = ETH_ALEN, |
| .ether = {{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }}, |
| }, default_ib_bcast = { |
| .length = INFINIBAND_ALEN, |
| .infiniband = { |
| 0x00, 0xff, 0xff, 0xff, 0xff, 0x12, 0x40, 0x1b, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0xff, 0xff, 0xff, 0xff |
| }, |
| }; |
| |
| assert(ifindex > 0); |
| assert(link); |
| assert(hw_addr); |
| |
| switch (arp_type) { |
| case ARPHRD_ETHER: |
| return _bind_raw_socket(ifindex, link, xid, |
| hw_addr, |
| (bcast_addr && !hw_addr_is_null(bcast_addr)) ? bcast_addr : &default_eth_bcast, |
| arp_type, port, so_priority_set, so_priority); |
| |
| case ARPHRD_INFINIBAND: |
| return _bind_raw_socket(ifindex, link, xid, |
| &HW_ADDR_NULL, |
| (bcast_addr && !hw_addr_is_null(bcast_addr)) ? bcast_addr : &default_ib_bcast, |
| arp_type, port, so_priority_set, so_priority); |
| default: |
| return -EINVAL; |
| } |
| } |
| |
| int dhcp_network_bind_udp_socket(int ifindex, be32_t address, uint16_t port, int ip_service_type) { |
| union sockaddr_union src = { |
| .in.sin_family = AF_INET, |
| .in.sin_port = htobe16(port), |
| .in.sin_addr.s_addr = address, |
| }; |
| _cleanup_close_ int s = -EBADF; |
| int r; |
| |
| s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); |
| if (s < 0) |
| return -errno; |
| |
| if (ip_service_type >= 0) |
| r = setsockopt_int(s, IPPROTO_IP, IP_TOS, ip_service_type); |
| else |
| r = setsockopt_int(s, IPPROTO_IP, IP_TOS, IPTOS_CLASS_CS6); |
| if (r < 0) |
| return r; |
| |
| r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true); |
| if (r < 0) |
| return r; |
| |
| if (ifindex > 0) { |
| r = socket_bind_to_ifindex(s, ifindex); |
| if (r < 0) |
| return r; |
| } |
| |
| if (port == DHCP_PORT_SERVER) { |
| r = setsockopt_int(s, SOL_SOCKET, SO_BROADCAST, true); |
| if (r < 0) |
| return r; |
| if (address == INADDR_ANY) { |
| /* IP_PKTINFO filter should not be applied when packets are |
| allowed to enter/leave through the interface other than |
| DHCP server sits on(BindToInterface option). */ |
| r = setsockopt_int(s, IPPROTO_IP, IP_PKTINFO, true); |
| if (r < 0) |
| return r; |
| } |
| } else { |
| r = setsockopt_int(s, IPPROTO_IP, IP_FREEBIND, true); |
| if (r < 0) |
| return r; |
| } |
| |
| if (bind(s, &src.sa, sizeof(src.in)) < 0) |
| return -errno; |
| |
| return TAKE_FD(s); |
| } |
| |
| int dhcp_network_send_raw_socket( |
| int s, |
| const union sockaddr_union *link, |
| const void *packet, |
| size_t len) { |
| |
| /* Do not add assert(s >= 0) here, as this is called in fuzz-dhcp-server, and in that case this |
| * function should fail with negative errno. */ |
| |
| assert(link); |
| assert(packet); |
| assert(len > 0); |
| |
| if (sendto(s, packet, len, 0, &link->sa, SOCKADDR_LL_LEN(link->ll)) < 0) |
| return -errno; |
| |
| return 0; |
| } |
| |
| int dhcp_network_send_udp_socket( |
| int s, |
| be32_t address, |
| uint16_t port, |
| const void *packet, |
| size_t len) { |
| |
| union sockaddr_union dest = { |
| .in.sin_family = AF_INET, |
| .in.sin_port = htobe16(port), |
| .in.sin_addr.s_addr = address, |
| }; |
| |
| assert(s >= 0); |
| assert(packet); |
| assert(len > 0); |
| |
| if (sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in)) < 0) |
| return -errno; |
| |
| return 0; |
| } |
