088b6ba264
(also, fix some whitespace/indentation issues, and avoid "index" as identifier in order to not clash against libc's "index()" call)
92 lines
3.9 KiB
C
92 lines
3.9 KiB
C
/***
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This file is part of systemd.
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Copyright (C) 2014 Axis Communications AB. All rights reserved.
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <linux/filter.h>
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#include "util.h"
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#include "ipv4ll-internal.h"
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int arp_network_send_raw_socket(int fd, const union sockaddr_union *link,
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const struct ether_arp *arp) {
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int r;
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assert(arp);
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assert(link);
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assert(fd >= 0);
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r = sendto(fd, arp, sizeof(struct ether_arp), 0, &link->sa, sizeof(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 arp_network_bind_raw_socket(int ifindex, union sockaddr_union *link) {
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static const 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(struct ether_arp), 1, 0), /* packet >= arp packet ? */
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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(struct ether_arp, ea_hdr.ar_hrd)), /* A <- header */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header == ethernet ? */
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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(struct ether_arp, ea_hdr.ar_pro)), /* A <- protocol */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 1, 0), /* protocol == IP ? */
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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(struct ether_arp, ea_hdr.ar_op)), /* A <- operation */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 0, 1), /* protocol == request ? */
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BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1), /* protocol == reply ? */
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BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
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BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
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};
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struct sock_fprog fprog = {
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.len = ELEMENTSOF(filter),
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.filter = (struct sock_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(PF_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(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.sll_family = AF_PACKET;
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link->ll.sll_protocol = htons(ETH_P_ARP);
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link->ll.sll_ifindex = ifindex;
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link->ll.sll_halen = ETH_ALEN;
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memset(link->ll.sll_addr, 0xff, ETH_ALEN);
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r = bind(s, &link->sa, sizeof(link->ll));
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if (r < 0)
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return -errno;
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r = s;
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s = -1;
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return r;
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}
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