sdhcp

simple dhcp client
git clone git://git.2f30.org/sdhcp.git
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commit f397bb3ea1de20c1cac1baf2e091f2ec8c79ec82
parent 219b8fe1c38097c37de89b0c8c2aa771ebe1daff
Author: Michael Forney <mforney@mforney.org>
Date:   Wed, 14 Nov 2018 18:40:35 -0800

Ignore unexpected DHCP messages

Diffstat:
sdhcp.c | 92++++++++++++++++++++++++++++++++++++++++---------------------------------------
1 file changed, 47 insertions(+), 45 deletions(-)

diff --git a/sdhcp.c b/sdhcp.c @@ -356,30 +356,30 @@ Init: alarm(1); goto Selecting; Selecting: - switch (dhcprecv()) { - case DHCPoffer: - alarm(0); - memcpy(client, bp.yiaddr, sizeof(client)); - optget(&bp, server, ODserverid, sizeof(server)); - optget(&bp, mask, OBmask, sizeof(mask)); - optget(&bp, router, OBrouter, sizeof(router)); - optget(&bp, dns, OBdnsserver, sizeof(dns)); - optget(&bp, &t1, ODlease, sizeof(t1)); - t1 = ntohl(t1); - dhcpsend(DHCPrequest, Broadcast); - goto Requesting; - case Timeout: - goto Init; - default: - goto Selecting; + for (;;) { + switch (dhcprecv()) { + case DHCPoffer: + alarm(0); + memcpy(client, bp.yiaddr, sizeof(client)); + optget(&bp, server, ODserverid, sizeof(server)); + optget(&bp, mask, OBmask, sizeof(mask)); + optget(&bp, router, OBrouter, sizeof(router)); + optget(&bp, dns, OBdnsserver, sizeof(dns)); + optget(&bp, &t1, ODlease, sizeof(t1)); + t1 = ntohl(t1); + dhcpsend(DHCPrequest, Broadcast); + goto Requesting; + case Timeout: + goto Init; + } } Requesting: - switch (dhcprecv()) { - case DHCPoffer: - goto Requesting; /* ignore other offers. */ - case DHCPack: - acceptlease(); - goto Bound; + for (;;) { + switch (dhcprecv()) { + case DHCPack: + acceptlease(); + goto Bound; + } } Bound: fputs("Congrats! You should be on the 'net.\n", stdout); @@ -388,33 +388,35 @@ Bound: exit(0); forked = 1; } - switch (dhcprecv()) { - case DHCPoffer: - case DHCPack: - case DHCPnak: - goto Bound; /* discard offer, ACK or NAK */ - case Timeout: - dhcpsend(DHCPrequest, Unicast); - goto Renewing; + for (;;) { + switch (dhcprecv()) { + case Timeout: + dhcpsend(DHCPrequest, Unicast); + goto Renewing; + } } Renewing: - switch (dhcprecv()) { - case DHCPack: - acceptlease(); - goto Bound; - case DHCPnak: - goto Init; - case Timeout: - dhcpsend(DHCPrequest, Broadcast); - goto Rebinding; + for (;;) { + switch (dhcprecv()) { + case DHCPack: + acceptlease(); + goto Bound; + case DHCPnak: + goto Init; + case Timeout: + dhcpsend(DHCPrequest, Broadcast); + goto Rebinding; + } } Rebinding: - switch (dhcprecv()) { - case DHCPnak: /* lease expired */ - goto Init; - case DHCPack: - acceptlease(); - goto Bound; + for (;;) { + switch (dhcprecv()) { + case DHCPnak: /* lease expired */ + goto Init; + case DHCPack: + acceptlease(); + goto Bound; + } } }