996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen/***
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen This file is part of systemd.
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen Copyright (C) 2014 Axis Communications AB. All rights reserved.
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen Copyright (C) 2015 Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen systemd is free software; you can redistribute it and/or modify it
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen under the terms of the GNU Lesser General Public License as published by
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen the Free Software Foundation; either version 2.1 of the License, or
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen (at your option) any later version.
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen systemd is distributed in the hope that it will be useful, but
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen WITHOUT ANY WARRANTY; without even the implied warranty of
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen Lesser General Public License for more details.
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen You should have received a copy of the GNU Lesser General Public License
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen along with systemd; If not, see <http://www.gnu.org/licenses/>.
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen***/
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen#include <linux/filter.h>
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen#include <arpa/inet.h>
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen#include "arp-util.h"
3ffd4af22052963e7a29431721ee204e634bea75Lennart Poettering#include "fd-util.h"
3ffd4af22052963e7a29431721ee204e634bea75Lennart Poettering#include "util.h"
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersenint arp_network_bind_raw_socket(int ifindex, be32_t address, const struct ether_addr *eth_mac) {
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen struct sock_filter filter[] = {
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(struct ether_arp), 1, 0), /* packet >= arp packet ? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_hrd)), /* A <- header */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header == ethernet ? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_pro)), /* A <- protocol */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 1, 0), /* protocol == IP ? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_hln)), /* A <- hardware address length */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, sizeof(struct ether_addr), 1, 0), /* length == sizeof(ether_addr)? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_pln)), /* A <- protocol address length */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, sizeof(struct in_addr), 1, 0), /* length == sizeof(in_addr) ? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_op)), /* A <- operation */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 2, 0), /* protocol == request ? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 1, 0), /* protocol == reply ? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen /* Sender Hardware Address must be different from our own */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_IMM, htobe32(*((uint32_t *) eth_mac))), /* A <- 4 bytes of client's MAC */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_sha)), /* A <- 4 bytes of SHA */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 6), /* A == 0 ? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_IMM, htobe16(*((uint16_t *) (((char *) eth_mac) + 4)))), /* A <- remainder of client's MAC */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, arp_sha) + 4), /* A <- remainder of SHA */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 1), /* A == 0 ? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen /* Sender Protocol Address or Target Protocol Address must be equal to the one we care about*/
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_IMM, htobe32(address)), /* A <- clients IP */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_spa)), /* A <- SPA */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* X xor A */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 1), /* A == 0 ? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_IMM, htobe32(address)), /* A <- clients IP */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_tpa)), /* A <- TPA */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* X xor A */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 1), /* A == 0 ? */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen };
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen struct sock_fprog fprog = {
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .len = ELEMENTSOF(filter),
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .filter = (struct sock_filter*) filter
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen };
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen union sockaddr_union link = {
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ll.sll_family = AF_PACKET,
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ll.sll_protocol = htons(ETH_P_ARP),
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ll.sll_ifindex = ifindex,
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ll.sll_halen = ETH_ALEN,
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ll.sll_addr = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen };
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen _cleanup_close_ int s = -1;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen int r;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen assert(ifindex > 0);
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen s = socket(PF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen if (s < 0)
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen return -errno;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen if (r < 0)
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen return -errno;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen r = bind(s, &link.sa, sizeof(link.ll));
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen if (r < 0)
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen return -errno;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen r = s;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen s = -1;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen return r;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen}
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersenstatic int arp_send_packet(int fd, int ifindex,
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen be32_t pa, const struct ether_addr *ha,
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen bool announce) {
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen union sockaddr_union link = {
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ll.sll_family = AF_PACKET,
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ll.sll_protocol = htons(ETH_P_ARP),
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ll.sll_ifindex = ifindex,
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ll.sll_halen = ETH_ALEN,
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ll.sll_addr = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen };
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen struct ether_arp arp = {
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ea_hdr.ar_hrd = htons(ARPHRD_ETHER), /* HTYPE */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ea_hdr.ar_pro = htons(ETHERTYPE_IP), /* PTYPE */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ea_hdr.ar_hln = ETH_ALEN, /* HLEN */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ea_hdr.ar_pln = sizeof(be32_t), /* PLEN */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen .ea_hdr.ar_op = htons(ARPOP_REQUEST), /* REQUEST */
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen };
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen int r;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen assert(fd >= 0);
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen assert(pa != 0);
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen assert(ha);
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen memcpy(&arp.arp_sha, ha, ETH_ALEN);
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen memcpy(&arp.arp_tpa, &pa, sizeof(pa));
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen if (announce)
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen memcpy(&arp.arp_spa, &pa, sizeof(pa));
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen r = sendto(fd, &arp, sizeof(struct ether_arp), 0, &link.sa, sizeof(link.ll));
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen if (r < 0)
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen return -errno;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen return 0;
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen}
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersenint arp_send_probe(int fd, int ifindex,
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen be32_t pa, const struct ether_addr *ha) {
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen return arp_send_packet(fd, ifindex, pa, ha, false);
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen}
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersenint arp_send_announcement(int fd, int ifindex,
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen be32_t pa, const struct ether_addr *ha) {
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen return arp_send_packet(fd, ifindex, pa, ha, true);
996d16975b4d802335188a3be2bbc3635c1287f3Tom Gundersen}