245 lines
12 KiB
C
245 lines
12 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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/***
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Copyright © 2013 Intel Corporation. All rights reserved.
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***/
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#include <errno.h>
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#include <net/ethernet.h>
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#include <net/if.h>
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#include <net/if_arp.h>
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#include <stdio.h>
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#include <string.h>
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#include <linux/filter.h>
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#include <linux/if_infiniband.h>
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#include <linux/if_packet.h>
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#include "dhcp-internal.h"
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#include "fd-util.h"
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#include "socket-util.h"
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#include "unaligned.h"
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static int _bind_raw_socket(int ifindex, union sockaddr_union *link,
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uint32_t xid,
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const uint8_t *bcast_addr,
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size_t bcast_addr_len,
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const struct ether_addr *eth_mac,
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uint16_t arp_type, uint8_t dhcp_hlen,
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uint16_t port) {
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struct sock_filter filter[] = {
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BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */
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BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(DHCPPacket), 1, 0), /* packet >= DHCPPacket ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol == UDP ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags */
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BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x20), /* A <- A & 0x20 (More Fragments bit) */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags + Fragment offset */
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BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff (Fragment offset) */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)), /* A <- UDP destination port */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, port, 1, 0), /* UDP destination port == DHCP client port ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.op)), /* A <- DHCP op */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, BOOTREPLY, 1, 0), /* op == BOOTREPLY ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.htype)), /* A <- DHCP header type */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, arp_type, 1, 0), /* header type == arp_type ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.xid)), /* A <- client identifier */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, xid, 1, 0), /* client identifier == xid ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.hlen)), /* A <- MAC address length */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, dhcp_hlen, 1, 0), /* address length == dhcp_hlen ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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/* We only support MAC address length to be either 0 or 6 (ETH_ALEN). Optionally
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* compare chaddr for ETH_ALEN bytes. */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETH_ALEN, 0, 12), /* A (the MAC address length) == ETH_ALEN ? */
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BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be32(ð_mac->ether_addr_octet[0])), /* A <- 4 bytes of client's MAC */
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BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
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BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr)), /* A <- 4 bytes of MAC from dhcp.chaddr */
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BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be16(ð_mac->ether_addr_octet[4])), /* A <- remainder of client's MAC */
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BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
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BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr) + 4), /* A <- remainder of MAC from dhcp.chaddr */
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BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.magic)), /* A <- DHCP magic cookie */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_MAGIC_COOKIE, 1, 0), /* cookie == DHCP magic cookie ? */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
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};
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struct sock_fprog fprog = {
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.len = ELEMENTSOF(filter),
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.filter = filter
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};
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_cleanup_close_ int s = -1;
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int r;
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assert(ifindex > 0);
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assert(link);
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s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
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if (s < 0)
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return -errno;
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r = setsockopt_int(s, SOL_PACKET, PACKET_AUXDATA, true);
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if (r < 0)
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return r;
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r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
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if (r < 0)
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return -errno;
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link->ll = (struct sockaddr_ll) {
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.sll_family = AF_PACKET,
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.sll_protocol = htobe16(ETH_P_IP),
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.sll_ifindex = ifindex,
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.sll_hatype = htobe16(arp_type),
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.sll_halen = bcast_addr_len,
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};
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memcpy(link->ll.sll_addr, bcast_addr, bcast_addr_len); /* We may overflow link->ll. link->ll_buffer ensures we have enough space. */
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r = bind(s, &link->sa, SOCKADDR_LL_LEN(link->ll));
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if (r < 0)
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return -errno;
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return TAKE_FD(s);
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}
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int dhcp_network_bind_raw_socket(int ifindex, union sockaddr_union *link, uint32_t xid,
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const uint8_t *mac_addr, size_t mac_addr_len,
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const uint8_t *bcast_addr, size_t bcast_addr_len,
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uint16_t arp_type, uint16_t port) {
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static const uint8_t eth_bcast[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
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/* Default broadcast address for IPoIB */
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static const uint8_t ib_bcast[] = {
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0x00, 0xff, 0xff, 0xff, 0xff, 0x12, 0x40, 0x1b,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0xff, 0xff, 0xff, 0xff
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};
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struct ether_addr eth_mac = { { 0, 0, 0, 0, 0, 0 } };
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const uint8_t *default_bcast_addr;
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size_t expected_bcast_addr_len;
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uint8_t dhcp_hlen = 0;
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if (arp_type == ARPHRD_ETHER) {
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assert_return(mac_addr_len == ETH_ALEN, -EINVAL);
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memcpy(ð_mac, mac_addr, ETH_ALEN);
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dhcp_hlen = ETH_ALEN;
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default_bcast_addr = eth_bcast;
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expected_bcast_addr_len = ETH_ALEN;
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} else if (arp_type == ARPHRD_INFINIBAND) {
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default_bcast_addr = ib_bcast;
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expected_bcast_addr_len = INFINIBAND_ALEN;
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} else
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return -EINVAL;
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if (bcast_addr && bcast_addr_len > 0)
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assert_return(bcast_addr_len == expected_bcast_addr_len, -EINVAL);
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else {
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bcast_addr = default_bcast_addr;
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bcast_addr_len = expected_bcast_addr_len;
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}
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return _bind_raw_socket(ifindex, link, xid, bcast_addr, bcast_addr_len,
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ð_mac, arp_type, dhcp_hlen, port);
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}
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int dhcp_network_bind_udp_socket(int ifindex, be32_t address, uint16_t port, int ip_service_type) {
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union sockaddr_union src = {
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.in.sin_family = AF_INET,
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.in.sin_port = htobe16(port),
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.in.sin_addr.s_addr = address,
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};
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_cleanup_close_ int s = -1;
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int r;
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s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
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if (s < 0)
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return -errno;
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if (ip_service_type >= 0)
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r = setsockopt_int(s, IPPROTO_IP, IP_TOS, ip_service_type);
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else
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r = setsockopt_int(s, IPPROTO_IP, IP_TOS, IPTOS_CLASS_CS6);
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if (r < 0)
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return r;
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r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
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if (r < 0)
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return r;
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if (ifindex > 0) {
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r = socket_bind_to_ifindex(s, ifindex);
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if (r < 0)
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return r;
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}
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if (address == INADDR_ANY) {
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r = setsockopt_int(s, IPPROTO_IP, IP_PKTINFO, true);
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if (r < 0)
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return r;
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r = setsockopt_int(s, SOL_SOCKET, SO_BROADCAST, true);
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if (r < 0)
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return r;
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} else {
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r = setsockopt_int(s, IPPROTO_IP, IP_FREEBIND, true);
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if (r < 0)
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return r;
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}
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r = bind(s, &src.sa, sizeof(src.in));
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if (r < 0)
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return -errno;
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return TAKE_FD(s);
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}
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int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link,
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const void *packet, size_t len) {
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int r;
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assert(link);
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assert(packet);
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assert(len);
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r = sendto(s, packet, len, 0, &link->sa, SOCKADDR_LL_LEN(link->ll));
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if (r < 0)
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return -errno;
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return 0;
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}
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int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port,
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const void *packet, size_t len) {
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union sockaddr_union dest = {
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.in.sin_family = AF_INET,
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.in.sin_port = htobe16(port),
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.in.sin_addr.s_addr = address,
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};
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int r;
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assert(s >= 0);
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assert(packet);
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assert(len);
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r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in));
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if (r < 0)
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return -errno;
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return 0;
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}
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