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| author | David Gibson | 2012-02-24 01:23:28 +0100 |
|---|---|---|
| committer | Jan Kiszka | 2012-02-27 14:55:07 +0100 |
| commit | 90d7416ab13113ccd3891435eea8715c5f503460 (patch) | |
| tree | c1ef264562f2606ffaaef7bef1e8252810ecbe27 | |
| parent | slirp: Refactor if_start (diff) | |
| download | qemu-90d7416ab13113ccd3891435eea8715c5f503460.tar.gz qemu-90d7416ab13113ccd3891435eea8715c5f503460.tar.xz qemu-90d7416ab13113ccd3891435eea8715c5f503460.zip | |
slirp: Fix assertion failure on rejected DHCP requests
The guest network stack might DHCPREQUEST an address that the slirp built
in dhcp server can't let it have - for example if the guest has an old
leases file from another network configuration. In this case the dhcp
server should and does reject the request and prepares to send a DHCPNAK
to the client.
However, in this case the daddr variable in bootp_reply() is set to
0.0.0.0. Shortly afterwards, it unconditionally attempts to pre-insert the
new client address into the ARP table. This causes an assertion failure in
arp_address_add() because of the 0.0.0.0 address.
According to RFC2131, DHCPNAK messages for clients on the same subnet
must be sent to the broadcast address (S3.2, subpoint 2).
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
| -rw-r--r-- | slirp/bootp.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/slirp/bootp.c b/slirp/bootp.c index efd1fe777a..64eac7d101 100644 --- a/slirp/bootp.c +++ b/slirp/bootp.c @@ -200,7 +200,8 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp) daddr.sin_addr = preq_addr; memcpy(bc->macaddr, client_ethaddr, ETH_ALEN); } else { - daddr.sin_addr.s_addr = 0; + /* DHCPNAKs should be sent to broadcast */ + daddr.sin_addr.s_addr = 0xffffffff; } } else { bc = find_addr(slirp, &daddr.sin_addr, bp->bp_hwaddr); |