tcpdump mailing list archives
Re: vlan tagged packets and libpcap breakage
From: Ani Sinha <ani () aristanetworks com>
Date: Mon, 10 Dec 2012 16:11:34 -0800 (PST)
On Thu, 6 Dec 2012, Michael Richardson wrote:
Date: Thu, 6 Dec 2012 17:59:13 From: Michael Richardson <mcr () sandelman ca> To: Eric W. Biederman <ebiederm () xmission com> Cc: ani () aristanetworks com, tcpdump-workers () lists tcpdump org, netdev () vger kernel org, Francesco Ruggeri <fruggeri () aristanetworks com> Subject: Re: [tcpdump-workers] vlan tagged packets and libpcap breakage"Eric" == Eric W Biederman <ebiederm () xmission com> writes:Eric> It is a bit odd that you are indenting with spaces instead of tabs Eric> in a file that is indented with tab. Again libpcap isn't my code so I Eric> don't care but someone else might.
Here's an updated patch. I have converted spaces to tabs consistent with rest of the file. I have also set up github and sent a pull request : commit b977ebd9d9608bb8a8e4927e7a6286bdfd6b94a8 Author: Ani Sinha <ani () aristanetworks com> Date: Mon Dec 10 14:58:15 2012 -0800 Linux kernel 3.0 uses TP_STATUS_VLAN_VALID flag in packet auxilliary data aux->tp_status to indicate a packet tagged with a valid vlan ID 0 with another packet that is not vlan tagged. Use this flag to check for the presence of a vlan tagged packet. Also be careful not to cause any breakage when libpcap is compiled against a newer kernel (>=3.0) and used on top of an older kernel that does not use this flag. Signed-off-by: Ani Sinha <ani () aristanetworks com> diff --git a/pcap-linux.c b/pcap-linux.c index a42c3ac..ffcabdf 100644 --- a/pcap-linux.c +++ b/pcap-linux.c @@ -133,6 +133,7 @@ static const char rcsid[] _U_ = #include <sys/utsname.h> #include <sys/mman.h> #include <linux/if.h> +#include <linux/if_packet.h> #include <netinet/in.h> #include <linux/if_ether.h> #include <net/if_arp.h> @@ -1543,7 +1544,13 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) continue; aux = (struct tpacket_auxdata *)CMSG_DATA(cmsg); - if (aux->tp_vlan_tci == 0) +#if defined(TP_STATUS_VLAN_VALID) + if ((aux->tp_vlan_tci == 0) && !(aux->tp_status & TP_STATUS_VLAN_VALID)) +#else + if (aux->tp_vlan_tci == 0) /* this is ambigious but without the + TP_STATUS_VLAN_VALID flag, there is + nothing that we can do */ +#endif continue; len = packet_len > iov.iov_len ? iov.iov_len : packet_len; @@ -3936,7 +3943,12 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, } #ifdef HAVE_TPACKET2 - if (handle->md.tp_version == TPACKET_V2 && h.h2->tp_vlan_tci && + if ((handle->md.tp_version == TPACKET_V2) && +#if defined(TP_STATUS_VLAN_VALID) + (h.h2->tp_vlan_tci || (h.h2->tp_status & TP_STATUS_VLAN_VALID)) && +#else + h.h2->tp_vlan_tci && +#endif handle->md.vlan_offset != -1 && tp_snaplen >= (unsigned int) handle->md.vlan_offset) { struct vlan_tag *tag; _______________________________________________ tcpdump-workers mailing list tcpdump-workers () lists tcpdump org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
Current thread:
- Re: vlan tagged packets and libpcap breakage, (continued)
- Message not available
- Re: vlan tagged packets and libpcap breakage Eric W. Biederman (Nov 18)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 06)
- Re: vlan tagged packets and libpcap breakage Eric W. Biederman (Dec 06)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 06)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 06)
- Re: vlan tagged packets and libpcap breakage Eric W. Biederman (Dec 06)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 06)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 06)
- Re: vlan tagged packets and libpcap breakage Eric W. Biederman (Dec 06)
- Re: vlan tagged packets and libpcap breakage Michael Richardson (Dec 06)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 10)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 11)
- Re: vlan tagged packets and libpcap breakage Eric Dumazet (Dec 13)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 11)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 11)
- Re: vlan tagged packets and libpcap breakage Stephen Hemminger (Dec 13)
- Message not available
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 12)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 12)
- Re: vlan tagged packets and libpcap breakage Daniel Borkmann (Dec 13)
- Re: vlan tagged packets and libpcap breakage Ani Sinha (Dec 13)
- Re: vlan tagged packets and libpcap breakage Daniel Borkmann (Dec 13)