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Add promiscuous mode capture support w/ tcpdump #3333

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hbhasker opened this issue Jul 22, 2020 · 1 comment
Open

Add promiscuous mode capture support w/ tcpdump #3333

hbhasker opened this issue Jul 22, 2020 · 1 comment
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area: compatibility area: networking type: enhancement

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@hbhasker
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@hbhasker hbhasker commented Jul 22, 2020

#173 is now fixed and tcpdump mostly works except when using it with gVisor in promiscuous mode. This requires supporting a few missing AF_PACKET features namely

https://man7.org/linux/man-pages/man7/packet.7.html

PACKET_ADD_MEMBERSHIP
PACKET_DROP_MEMBERSHIP
Packet sockets can be used to configure physical-layer multi‐
casting and promiscuous mode. PACKET_ADD_MEMBERSHIP adds a
binding and PACKET_DROP_MEMBERSHIP drops it. They both expect
a packet_mreq structure as argument:

              struct packet_mreq {
                  int            mr_ifindex;    /* interface index */
                  unsigned short mr_type;       /* action */
                  unsigned short mr_alen;       /* address length */
                  unsigned char  mr_address[8]; /* physical-layer address */
              };

          mr_ifindex contains the interface index for the interface
          whose status should be changed.  The mr_type field specifies
          which action to perform.  PACKET_MR_PROMISC enables receiving
          all packets on a shared medium (often known as "promiscuous
          mode"), PACKET_MR_MULTICAST binds the socket to the physical-
          layer multicast group specified in mr_address and mr_alen, and
          PACKET_MR_ALLMULTI sets the socket up to receive all multicast
          packets arriving at the interface.

          In addition, the traditional ioctls SIOCSIFFLAGS, SIOCADD‐
          MULTI, SIOCDELMULTI can be used for the same purpose.

tcpdump also seems to use

PACKET_AUXDATA (since Linux 2.6.21)
If this binary option is enabled, the packet socket passes a
metadata structure along with each packet in the recvmsg(2)
control field. The structure can be read with cmsg(3). It is
defined as

              struct tpacket_auxdata {
                  __u32 tp_status;
                  __u32 tp_len;      /* packet length */
                  __u32 tp_snaplen;  /* captured length */
                  __u16 tp_mac;
                  __u16 tp_net;
                  __u16 tp_vlan_tci;
                  __u16 tp_vlan_tpid; /* Since Linux 3.14; earlier, these
                                         were unused padding bytes */
              };

Separately we may at some point need to add support for PACKET_RX_RING etc for high speed packet capture but that is a very low priority.

@hbhasker hbhasker assigned hbhasker and unassigned hbhasker Jul 22, 2020
@hbhasker hbhasker added area: compatibility area: networking labels Jul 22, 2020
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@github-actions github-actions bot commented Oct 21, 2020

This issue is stale because it has been open 90 days with no activity. Remove the stale label or comment or this will be closed in 30 days.

@github-actions github-actions bot added the stale label Oct 21, 2020
@tamird tamird added type: enhancement and removed stale labels Jun 8, 2021
@tamird tamird reopened this Jun 8, 2021
copybara-service bot pushed a commit that referenced this issue Jun 19, 2021
tcpdump is largely supported. We've also chose not to implement writeable
AF_PACKET sockets, and there's a bug specifically for promiscuous mode (#3333).

Fixes #173.

dns

PiperOrigin-RevId: 380299982
copybara-service bot pushed a commit that referenced this issue Jun 19, 2021
tcpdump is largely supported. We've also chose not to implement writeable
AF_PACKET sockets, and there's a bug specifically for promiscuous mode (#3333).

Fixes #173.

PiperOrigin-RevId: 380299982
copybara-service bot pushed a commit that referenced this issue Jun 21, 2021
tcpdump is largely supported. We've also chose not to implement writeable
AF_PACKET sockets, and there's a bug specifically for promiscuous mode (#3333).

Fixes #173.

PiperOrigin-RevId: 380299982
copybara-service bot pushed a commit that referenced this issue Jun 22, 2021
tcpdump is largely supported. We've also chose not to implement writeable
AF_PACKET sockets, and there's a bug specifically for promiscuous mode (#3333).

Fixes #173.

PiperOrigin-RevId: 380299982
copybara-service bot pushed a commit that referenced this issue Jun 22, 2021
tcpdump is largely supported. We've also chose not to implement writeable
AF_PACKET sockets, and there's a bug specifically for promiscuous mode (#3333).

Fixes #173.

PiperOrigin-RevId: 380733686
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