diff options
Diffstat (limited to 'src/libsystemd-network/src/dhcp-network.c')
| -rw-r--r-- | src/libsystemd-network/src/dhcp-network.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/src/libsystemd-network/src/dhcp-network.c b/src/libsystemd-network/src/dhcp-network.c new file mode 100644 index 0000000000..2cdadee730 --- /dev/null +++ b/src/libsystemd-network/src/dhcp-network.c @@ -0,0 +1,236 @@ +/*** + This file is part of systemd. + + Copyright (C) 2013 Intel Corporation. All rights reserved. + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <errno.h> +#include <net/ethernet.h> +#include <net/if_arp.h> +#include <stdio.h> +#include <string.h> +#include <sys/socket.h> + +#include <linux/filter.h> +#include <linux/if_infiniband.h> +#include <linux/if_packet.h> + +#include "systemd-basic/fd-util.h" +#include "systemd-basic/socket-util.h" +#include "systemd-network/dhcp-internal.h" + +static int _bind_raw_socket(int ifindex, union sockaddr_union *link, + uint32_t xid, const uint8_t *mac_addr, + size_t mac_addr_len, + const uint8_t *bcast_addr, + const struct ether_addr *eth_mac, + uint16_t arp_type, uint8_t dhcp_hlen) { + 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, DHCP_PORT_CLIENT, 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_B + BPF_ABS, offsetof(DHCPPacket, dhcp.hlen)), /* A <- MAC address length */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, dhcp_hlen, 1, 0), /* address length == dhcp_hlen ? */ + 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_IMM, htobe32(*((unsigned int *) eth_mac))), /* A <- 4 bytes of client's MAC */ + BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */ + BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr)), /* A <- 4 bytes of MAC from dhcp.chaddr */ + BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */ + 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_IMM, htobe16(*((unsigned short *) (((char *) eth_mac) + 4)))), /* A <- remainder of client's MAC */ + BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr) + 4), /* A <- remainder of MAC from dhcp.chaddr */ + BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */ + 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_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, 65535), /* return all */ + }; + struct sock_fprog fprog = { + .len = ELEMENTSOF(filter), + .filter = filter + }; + _cleanup_close_ int s = -1; + int r, on = 1; + + assert(ifindex > 0); + assert(link); + + s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); + if (s < 0) + return -errno; + + r = setsockopt(s, SOL_PACKET, PACKET_AUXDATA, &on, sizeof(on)); + if (r < 0) + return -errno; + + r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)); + if (r < 0) + return -errno; + + link->ll.sll_family = AF_PACKET; + link->ll.sll_protocol = htobe16(ETH_P_IP); + link->ll.sll_ifindex = ifindex; + link->ll.sll_hatype = htobe16(arp_type); + link->ll.sll_halen = mac_addr_len; + memcpy(link->ll.sll_addr, bcast_addr, mac_addr_len); + + r = bind(s, &link->sa, sizeof(link->ll)); + if (r < 0) + return -errno; + + r = s; + s = -1; + + return r; +} + +int dhcp_network_bind_raw_socket(int ifindex, union sockaddr_union *link, + uint32_t xid, const uint8_t *mac_addr, + size_t mac_addr_len, uint16_t arp_type) { + static const uint8_t eth_bcast[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; + /* Default broadcast address for IPoIB */ + static const uint8_t ib_bcast[] = { + 0x00, 0xff, 0xff, 0xff, 0xff, 0x12, 0x40, 0x1b, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0xff, 0xff, 0xff, 0xff + }; + struct ether_addr eth_mac = { { 0, 0, 0, 0, 0, 0 } }; + const uint8_t *bcast_addr = NULL; + uint8_t dhcp_hlen = 0; + + assert_return(mac_addr_len > 0, -EINVAL); + + if (arp_type == ARPHRD_ETHER) { + assert_return(mac_addr_len == ETH_ALEN, -EINVAL); + memcpy(ð_mac, mac_addr, ETH_ALEN); + bcast_addr = eth_bcast; + dhcp_hlen = ETH_ALEN; + } else if (arp_type == ARPHRD_INFINIBAND) { + assert_return(mac_addr_len == INFINIBAND_ALEN, -EINVAL); + bcast_addr = ib_bcast; + } else + return -EINVAL; + + return _bind_raw_socket(ifindex, link, xid, mac_addr, mac_addr_len, + bcast_addr, ð_mac, arp_type, dhcp_hlen); +} + +int dhcp_network_bind_udp_socket(be32_t address, uint16_t port) { + union sockaddr_union src = { + .in.sin_family = AF_INET, + .in.sin_port = htobe16(port), + .in.sin_addr.s_addr = address, + }; + _cleanup_close_ int s = -1; + int r, on = 1, tos = IPTOS_CLASS_CS6; + + s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); + if (s < 0) + return -errno; + + r = setsockopt(s, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)); + if (r < 0) + return -errno; + + r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); + if (r < 0) + return -errno; + + if (address == INADDR_ANY) { + r = setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on)); + if (r < 0) + return -errno; + + r = setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)); + if (r < 0) + return -errno; + } else { + r = setsockopt(s, IPPROTO_IP, IP_FREEBIND, &on, sizeof(on)); + if (r < 0) + return -errno; + } + + r = bind(s, &src.sa, sizeof(src.in)); + if (r < 0) + return -errno; + + r = s; + s = -1; + + return r; +} + +int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link, + const void *packet, size_t len) { + int r; + + assert(link); + assert(packet); + assert(len); + + r = sendto(s, packet, len, 0, &link->sa, sizeof(link->ll)); + if (r < 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, + }; + int r; + + assert(s >= 0); + assert(packet); + assert(len); + + r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in)); + if (r < 0) + return -errno; + + return 0; +} |