Multicast and hardware checksum
Subsystems (2)
Hello,
I have a machine on which I have an applications that sends multicast through eth interface with hardware tx checksum enabled. On the same machine I have mrouted running that routes the multicast traffic to a set of ppp interfaces. The packets that are received by the client have their checksum fixed on some number which is incorrect. If I disable tx checksum on the eth device the packets arrive with the proper checksum.
I still haven't followed the code paths to see how to fix this, maybe someone knows the relevant code and can find it faster.
Baruch
Quoted 7 lines · Baruch Even
I have a machine on which I have an applications that sends multicast through eth interface with hardware tx checksum enabled. On the same machine I have mrouted running that routes the multicast traffic to a set of ppp interfaces. The packets that are received by the client have their checksum fixed on some number which is incorrect. If I disable tx checksum on the eth device the packets arrive with the proper checksum.
Where is the client? On the same machine or behind a PPP link?
Cheers,
Signature · 4 lines
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txtQuoted 4 lines · Herbert Xu
Quoted 1 line · Baruch Even
I have a machine on which I have an applications that sends multicast through eth interface with hardware tx checksum enabled. On the same machine I have mrouted running that routes the multicast traffic to a set of ppp interfaces. The packets that are received by the client have their checksum fixed on some number which is incorrect. If I disable tx checksum on the eth device the packets arrive with the proper checksum.
Where is the client? On the same machine or behind a PPP link?
The clients are behind the ppp links.
As far as IGMP and multicast handling everything works, the packets are even forwarded over the ppp links but they arrive to the client with a bad checksum. I don't have the trace in front of me but I believe it was the UDP checksum that failed.
Baruch
Quoted 5 lines · Baruch Even
As far as IGMP and multicast handling everything works, the packets are even forwarded over the ppp links but they arrive to the client with a bad checksum. I don't have the trace in front of me but I believe it was the UDP checksum that failed.
What kind of a ppp device is this?
If you run a tcpdump either side of the ppp link do you see the same UDP checksum value?
Cheers,
Signature · 4 lines
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txtQuoted 7 lines · Herbert Xu
Quoted 1 line · Baruch Even
As far as IGMP and multicast handling everything works, the packets are even forwarded over the ppp links but they arrive to the client with a bad checksum. I don't have the trace in front of me but I believe it was the UDP checksum that failed.
What kind of a ppp device is this?
If you run a tcpdump either side of the ppp link do you see the same UDP checksum value?
This is a pptp link. I've checked the checksum on the receive side, I don't know on the sender side and I'll only be able to try it on Sunday.
Baruch
Quoted 10 lines · Baruch Even
Quoted 7 lines · Herbert Xu
Quoted 1 line · Baruch Even
As far as IGMP and multicast handling everything works, the packets are even forwarded over the ppp links but they arrive to the client with a bad checksum. I don't have the trace in front of me but I believe it was the UDP checksum that failed.
What kind of a ppp device is this?
If you run a tcpdump either side of the ppp link do you see the same UDP checksum value?
This is a pptp link. I've checked the checksum on the receive side, I don't know on the sender side and I'll only be able to try it on Sunday.
For completeness, the clients are Windows XP clients and the server is a
Linux machine. The tunnel is mppe encrypted so I believe that what
goes out on the client is the same as what got in on the server.
Baruch