Use an RFC2131-compliant exponential backoff delay.
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339804856b
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@ -23,9 +23,6 @@
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#include <stdint.h>
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#define NUMPACKETS 3 /* number of packets to send before delay */
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#define RETRY_DELAY 30 /* time in seconds to delay after sending NUMPACKETS */
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enum {
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LM_NONE = 0,
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LM_KERNEL,
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52
ndhc/state.c
52
ndhc/state.c
@ -47,15 +47,24 @@ dhcp_state_t dhcp_states[] = {
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{ 0, 0, 0, 0}, // NUM_STATES
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};
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static int delay_timeout(int numpackets)
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{
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int to = 64;
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char tot[] = { 4, 8, 16, 32, 64 };
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if (numpackets < sizeof tot)
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to = tot[numpackets];
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return to;
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}
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// Triggered after a DHCP lease request packet has been sent and no reply has
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// been received within the response wait time. If we've not exceeded the
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// maximum number of request retransmits, then send another packet and wait
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// again. Otherwise, return to the DHCP initialization state.
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static void requesting_timeout(struct client_state_t *cs)
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{
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if (cs->packetNum < NUMPACKETS) {
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if (cs->packetNum < 5) {
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send_selecting(cs->xid, cs->serverAddr, cs->requestedIP);
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cs->timeout = ((cs->packetNum == NUMPACKETS - 1) ? 10 : 2) * 1000;
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cs->timeout = delay_timeout(cs->packetNum);
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cs->packetNum++;
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} else {
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cs->dhcpState = DS_SELECTING;
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@ -151,8 +160,10 @@ static void an_packet(struct client_state_t *cs, struct dhcpmsg *packet,
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memcpy(&cs->lease, temp, 4);
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cs->lease = ntohl(cs->lease);
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cs->lease &= 0x0fffffff;
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if (cs->lease < RETRY_DELAY)
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cs->lease = RETRY_DELAY;
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if (cs->lease < 60) {
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log_warning("Server sent lease of <1m. Forcing lease to 1m.");
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cs->lease = 60;
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}
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}
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// Always use RFC2131 'default' values. It's not worth validating
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// the remote server values, if they even exist, for sanity.
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@ -202,35 +213,28 @@ static void selecting_packet(struct client_state_t *cs, struct dhcpmsg *packet,
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}
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}
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#define DELAY_SEC (((RETRY_DELAY - (RETRY_DELAY / NUMPACKETS)) / NUMPACKETS) + 1)
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// Triggered after a DHCP discover packet has been sent and no reply has
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// been received within the response wait time. If we've not exceeded the
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// maximum number of discover retransmits, then send another packet and wait
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// again. Otherwise, background or fail.
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static void selecting_timeout(struct client_state_t *cs)
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{
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if (cs->packetNum < NUMPACKETS) {
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if (cs->packetNum == 0)
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cs->xid = libc_random_u32();
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send_discover(cs->xid, cs->requestedIP);
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cs->timeout = DELAY_SEC * (cs->packetNum + 1) * 1000;
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cs->packetNum++;
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} else {
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if (cs->init) {
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if (client_config.background_if_no_lease) {
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log_line("No lease, going to background.");
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cs->init = 0;
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background(cs);
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} else if (client_config.abort_if_no_lease) {
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log_line("No lease, failing.");
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exit(EXIT_FAILURE);
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}
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if (cs->packetNum == 0)
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cs->xid = libc_random_u32();
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send_discover(cs->xid, cs->requestedIP);
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cs->timeout = delay_timeout(cs->packetNum);
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cs->packetNum++;
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if (cs->init && cs->packetNum >= 2) {
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if (client_config.background_if_no_lease) {
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log_line("No lease, going to background.");
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cs->init = 0;
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background(cs);
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} else if (client_config.abort_if_no_lease) {
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log_line("No lease, failing.");
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exit(EXIT_FAILURE);
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}
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cs->packetNum = 0;
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cs->timeout = RETRY_DELAY * 1000;
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}
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}
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#undef DELAY_SEC
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static void anfrelease(struct client_state_t *cs)
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{
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