Resend DHCPREQUEST in case server does not respond - sdhcp - simple dhcp client
(HTM) git clone git://git.codemadness.org/sdhcp
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---
(DIR) commit 5506c81d9930e68cfb29960a4211454fd46262b9
(DIR) parent 80bdf55532fadbf9398ce7e12fe494282f45f394
(HTM) Author: Michael Forney <mforney@mforney.org>
Date: Wed, 14 Nov 2018 18:40:39 -0800
Resend DHCPREQUEST in case server does not respond
The delays were chosen to follow section 4.1 of RFC 2131.
Diffstat:
M sdhcp.c | 29 +++++++++++++++++++----------
1 file changed, 19 insertions(+), 10 deletions(-)
---
(DIR) diff --git a/sdhcp.c b/sdhcp.c
@@ -386,7 +386,7 @@ calctimeout(int n, struct itimerspec *ts)
static void
run(void)
{
- int forked = 0;
+ int forked = 0, t;
struct itimerspec timeout = { 0 };
Init:
@@ -399,8 +399,6 @@ Selecting:
for (;;) {
switch (dhcprecv()) {
case DHCPoffer:
- timeout.it_value.tv_sec = 0;
- settimeout(0, &timeout);
memcpy(client, bp.yiaddr, sizeof(client));
optget(&bp, server, ODserverid, sizeof(server));
optget(&bp, mask, OBmask, sizeof(mask));
@@ -418,15 +416,26 @@ Selecting:
}
}
Requesting:
- dhcpsend(DHCPrequest, Broadcast);
- for (;;) {
- switch (dhcprecv()) {
- case DHCPack:
- goto Bound;
- case DHCPnak:
- goto Init;
+ for (t = 4; t <= 64; t *= 2) {
+ dhcpsend(DHCPrequest, Broadcast);
+ timeout.it_value.tv_sec = t;
+ settimeout(0, &timeout);
+ for (;;) {
+ switch (dhcprecv()) {
+ case DHCPack:
+ goto Bound;
+ case DHCPnak:
+ goto Init;
+ case Timeout0:
+ break;
+ default:
+ continue;
+ }
+ break;
}
}
+ /* no response from DHCPREQUEST after several attempts, go to INIT */
+ goto Init;
Bound:
acceptlease();
fputs("Congrats! You should be on the 'net.\n", stdout);