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Enforce upper and lower sanity bounds on lease times.

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This commit is contained in:
Nicholas J. Kain 2010-11-13 19:37:08 -05:00
parent aaca1ab6ef
commit 987ba12982
1 changed files with 9 additions and 4 deletions
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13
ndhc/ndhc.c
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@ -211,19 +211,18 @@ static void background(void)
write_pid(pidfile); write_pid(pidfile);
} }
/* Handle select timeout dropping to zero */
static void handle_timeout(void) static void handle_timeout(void)
{ {
time_t now = time(0); time_t now = time(0);
/* timeout dropped to zero */
switch (state) { switch (state) {
case INIT_SELECTING: case INIT_SELECTING:
if (packet_num < NUMPACKETS) { if (packet_num < NUMPACKETS) {
if (packet_num == 0) if (packet_num == 0)
xid = random_xid(); xid = random_xid();
/* broadcast */
/* send discover packet */ send_discover(xid, requested_ip);
send_discover(xid, requested_ip); /* broadcast */
timeout = now + ((packet_num == NUMPACKETS - 1) ? 4 : 2); timeout = now + ((packet_num == NUMPACKETS - 1) ? 4 : 2);
packet_num++; packet_num++;
@ -347,6 +346,7 @@ static void handle_packet(void)
/* Must be a DHCPOFFER to one of our xid's */ /* Must be a DHCPOFFER to one of our xid's */
if (*message == DHCPOFFER) { if (*message == DHCPOFFER) {
if ((temp = get_option(&packet, DHCP_SERVER_ID))) { if ((temp = get_option(&packet, DHCP_SERVER_ID))) {
/* Memcpy to a temp buffer to force alignment */
memcpy(&server_addr, temp, 4); memcpy(&server_addr, temp, 4);
xid = packet.xid; xid = packet.xid;
requested_ip = packet.yiaddr; requested_ip = packet.yiaddr;
@ -369,8 +369,13 @@ static void handle_packet(void)
log_line("No lease time received, assuming 1h."); log_line("No lease time received, assuming 1h.");
lease = 60 * 60; lease = 60 * 60;
} else { } else {
/* Memcpy to a temp buffer to force alignment */
memcpy(&lease, temp, 4); memcpy(&lease, temp, 4);
lease = ntohl(lease); lease = ntohl(lease);
/* Enforce upper and lower bounds on lease. */
lease &= 0x0fffffff;
if (lease < RETRY_DELAY)
lease = RETRY_DELAY;
} }
/* enter bound state */ /* enter bound state */