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Randomize the DHCP timeout by +[0,1000]ms to comply with RFC.

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This commit is contained in:
Nicholas J. Kain 2011-07-06 08:46:05 -04:00
parent daf42ccb29
commit a92cb1c4c6
2 changed files with 6 additions and 6 deletions
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8
ndhc/arp.c
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@ -1,5 +1,5 @@
/* arp.c - arp ping checking
* Time-stamp: <2011-07-05 16:00:42 njk>
* Time-stamp: <2011-07-06 08:41:06 njk>
*
* Copyright 2010-2011 Nicholas J. Kain <njkain@gmail.com>
*
@ -123,7 +123,7 @@ static void arp_set_bpf_basic(int fd)
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, (ETH_P_IP << 16) | 0x0604, 1, 0),
BPF_STMT(BPF_RET + BPF_K, 0),
// Sanity tests passed, so send all possible data.
BPF_STMT(BPF_RET + BPF_K, 0x0fffffff),
BPF_STMT(BPF_RET + BPF_K, 0x7fffffff),
};
static const struct sock_fprog sfp_arp = {
.len = sizeof sf_arp / sizeof sf_arp[0],
@ -164,13 +164,13 @@ static void arp_set_bpf_defense(struct client_state_t *cs, int fd)
// be passed along.
BPF_STMT(BPF_LD + BPF_W + BPF_ABS, 22),
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, mac4b, 1, 0),
BPF_STMT(BPF_RET + BPF_K, 0x0fffffff),
BPF_STMT(BPF_RET + BPF_K, 0x7fffffff),
// If the last two bytes of the ARP packet source hardware address
// do not equal our hardware address, then it's a conflict and should
// be passed along.
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 26),
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, mac2b, 1, 0),
BPF_STMT(BPF_RET + BPF_K, 0x0fffffff),
BPF_STMT(BPF_RET + BPF_K, 0x7fffffff),
// Packet announces our IP address and hardware address, so it requires
// no action.
BPF_STMT(BPF_RET + BPF_K, 0),

4
ndhc/state.c
View File

@ -56,7 +56,7 @@ static int delay_timeout(int numpackets)
char tot[] = { 4, 8, 16, 32, 64 };
if (numpackets < sizeof tot)
to = tot[numpackets];
return to * 1000;
return to * 1000 + rand() % 1000;
}
void reinit_selecting(struct client_state_t *cs, int timeout)
@ -192,7 +192,7 @@ static void an_packet(struct client_state_t *cs, struct dhcpmsg *packet,
} else {
memcpy(&cs->lease, temp, 4);
cs->lease = ntohl(cs->lease);
cs->lease &= 0x0fffffff;
cs->lease &= 0x7fffffff;
if (cs->lease < 60) {
log_warning("Server sent lease of <1m. Forcing lease to 1m.");
cs->lease = 60;