Re: [lwip-users] Pbuf volatile flag for received packets
> > >The behavior seems contradictory to the flag's description. Am I reading > it > >right? Should the comment be read only in the context of the lwip core, or > >maybe it only applies to transmitted packets? > > Yes, it only applies to tx packets. > > There's not much point in copying on the Rx side: the netif driver is > responsible to create pbufs that can live longer. You could argue that > pbufs might have to be copied when really enqueueing (e.g. in TCP Rx ooseq > and the like), but if you need to copy for tcpip_input, the driver has to > do it. > > Noted. Makes sense. Thank you. ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] Pbuf volatile flag for received packets
Am 16. März 2022 12:26:04 MEZ schrieb Jarno Malmari : >When passing received pbuf allocated with PBUF_TYPE_FLAG_DATA_VOLATILE >(e.g. PBUF_REF) to tcpip_input(), the pbuf is immediately queued without >checking the volatile flag. > >The comment on the volatile flag says: >/** Indicates the data stored in this pbuf can change. If this pbuf needs > * to be queued, it must be copied/duplicated. */ > >The behavior seems contradictory to the flag's description. Am I reading it >right? Should the comment be read only in the context of the lwip core, or >maybe it only applies to transmitted packets? Yes, it only applies to tx packets. There's not much point in copying on the Rx side: the netif driver is responsible to create pbufs that can live longer. You could argue that pbufs might have to be copied when really enqueueing (e.g. in TCP Rx ooseq and the like), but if you need to copy for tcpip_input, the driver has to do it. Regards, Simon ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
[lwip-users] Pbuf volatile flag for received packets
When passing received pbuf allocated with PBUF_TYPE_FLAG_DATA_VOLATILE (e.g. PBUF_REF) to tcpip_input(), the pbuf is immediately queued without checking the volatile flag. The comment on the volatile flag says: /** Indicates the data stored in this pbuf can change. If this pbuf needs * to be queued, it must be copied/duplicated. */ The behavior seems contradictory to the flag's description. Am I reading it right? Should the comment be read only in the context of the lwip core, or maybe it only applies to transmitted packets? Thanks. ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
