From: Denis Kenzior <denkenz@gmail.com>
To: connman@lists.linux.dev
Cc: Denis Kenzior <denkenz@gmail.com>
Subject: [PATCH] gdhcp: Allow client to work on veth devices
Date: Wed, 17 Apr 2024 11:22:24 -0500 [thread overview]
Message-ID: <20240417162243.3373629-1-denkenz@gmail.com> (raw)
veth devices do not compute a checksum over the entire message. They
simply pre-compute the pseudo-header portion and include this in the
checksum field. Support such devices by computing the partial checksum.
If the partial checksum matches, accept the packet.
---
gdhcp/client.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/gdhcp/client.c b/gdhcp/client.c
index c58c7be91143..2afa19e6e2ea 100644
--- a/gdhcp/client.c
+++ b/gdhcp/client.c
@@ -1355,8 +1355,13 @@ static int dhcp_recv_l2_packet(struct dhcp_packet *dhcp_pkt, int fd,
packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
check = packet.udp.check;
packet.udp.check = 0;
- if (check && check != dhcp_checksum(&packet, bytes))
- return -1;
+
+ if (check) {
+ uint16_t partial = ~dhcp_checksum(&packet, sizeof(struct iphdr));
+
+ if (check != partial && check != dhcp_checksum(&packet, bytes))
+ return -1;
+ }
memcpy(dhcp_pkt, &packet.data, bytes - (sizeof(packet.ip) +
sizeof(packet.udp)));
--
2.44.0
next reply other threads:[~2024-04-17 16:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-17 16:22 Denis Kenzior [this message]
2024-04-17 17:00 ` [PATCH] gdhcp: Allow client to work on veth devices patchwork-bot+connman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240417162243.3373629-1-denkenz@gmail.com \
--to=denkenz@gmail.com \
--cc=connman@lists.linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).