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arp: Take extra care to preserve last received ARP packet.

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This commit is contained in:
Nicholas J. Kain 2017-04-10 09:29:36 -04:00
parent 7af3e64a99
commit 369ff59cab
1 changed files with 8 additions and 13 deletions
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21
src/arp.c
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@ -78,11 +78,6 @@ static struct arp_data garp = {
void set_arp_relentless_def(bool v) { garp.relentless_def = v; }
static void arp_reply_clear(void)
{
memset(&garp.reply, 0, sizeof garp.reply);
}
static void arp_min_close_fd(struct client_state_t cs[static 1])
{
if (cs->arpFd < 0)
@ -103,7 +98,7 @@ static void arp_close_fd(struct client_state_t cs[static 1])
void arp_reset_state(struct client_state_t cs[static 1])
{
arp_close_fd(cs);
arp_reply_clear();
memset(&garp.reply, 0, sizeof garp.reply);
garp.last_conflict_ts = 0;
garp.gw_check_initpings = 0;
garp.arp_check_start_ts = 0;
@ -166,7 +161,6 @@ static int arp_open_fd(struct client_state_t cs[static 1], bool defense)
return -1;
}
epoll_add(cs->epollFd, cs->arpFd);
arp_reply_clear();
return 0;
}
@ -742,11 +736,12 @@ server_is_router:
bool arp_packet_get(struct client_state_t cs[static 1])
{
struct arpMsg amsg;
ssize_t r = 0;
size_t bytes_read = 0;
if (bytes_read < sizeof garp.reply) {
r = safe_read(cs->arpFd, (char *)&garp.reply + bytes_read,
sizeof garp.reply - bytes_read);
if (bytes_read < sizeof amsg) {
r = safe_read(cs->arpFd, (char *)&amsg + bytes_read,
sizeof amsg - bytes_read);
if (r == 0)
return false;
if (r < 0) {
@ -767,12 +762,12 @@ bool arp_packet_get(struct client_state_t cs[static 1])
// Emulate the BPF filters if they are not in use.
if (!garp.using_bpf &&
(!arp_validate_bpf(&garp.reply) ||
(!arp_validate_bpf(&amsg) ||
(cs->arp_is_defense &&
!arp_validate_bpf_defense(cs, &garp.reply)))) {
arp_reply_clear();
!arp_validate_bpf_defense(cs, &amsg)))) {
return false;
}
memcpy(&garp.reply, &amsg, sizeof garp.reply);
return true;
}