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/***
This file is part of systemd.
Copyright (C) 2014 Axis Communications AB. 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 <arpa/inet.h>
#include "util.h"
#include "ipv4ll-internal.h"
void arp_packet_init(struct ether_arp *arp) {
assert(arp);
memzero(arp, sizeof(struct ether_arp));
/* Header */
arp->ea_hdr.ar_hrd = htons(ARPHRD_ETHER); /* HTYPE */
arp->ea_hdr.ar_pro = htons(ETHERTYPE_IP); /* PTYPE */
arp->ea_hdr.ar_hln = ETH_ALEN; /* HLEN */
arp->ea_hdr.ar_pln = sizeof arp->arp_spa; /* PLEN */
arp->ea_hdr.ar_op = htons(ARPOP_REQUEST); /* REQUEST */
}
void arp_packet_probe(struct ether_arp *arp, be32_t pa, const struct ether_addr *ha) {
assert(ha);
arp_packet_init(arp);
memcpy(arp->arp_sha, ha, ETH_ALEN);
memcpy(arp->arp_tpa, &pa, sizeof(pa));
}
void arp_packet_announcement(struct ether_arp *arp, be32_t pa, const struct ether_addr *ha) {
assert(ha);
arp_packet_init(arp);
memcpy(arp->arp_sha, ha, ETH_ALEN);
memcpy(arp->arp_tpa, &pa, sizeof(pa));
memcpy(arp->arp_spa, &pa, sizeof(pa));
}
int arp_packet_verify_headers(struct ether_arp *arp) {
assert(arp);
if (arp->ea_hdr.ar_hrd != htons(ARPHRD_ETHER)) {
log_ipv4ll(NULL, "ignoring packet: header is not ARPHRD_ETHER");
return -EINVAL;
}
if (arp->ea_hdr.ar_pro != htons(ETHERTYPE_IP)) {
log_ipv4ll(NULL, "ignoring packet: protocol is not ETHERTYPE_IP");
return -EINVAL;
}
if (arp->ea_hdr.ar_op != htons(ARPOP_REQUEST) &&
arp->ea_hdr.ar_op != htons(ARPOP_REPLY)) {
log_ipv4ll(NULL, "ignoring packet: operation is not ARPOP_REQUEST or ARPOP_REPLY");
return -EINVAL;
}
return 0;
}
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