proc_pid_net(5) — Linux manual page

NAME | DESCRIPTION | SEE ALSO | COLOPHON

proc_pid_net(5)            File Formats Manual           proc_pid_net(5)

NAME         top

       /proc/pid/net/, /proc/net/ - network layer information

DESCRIPTION         top

       /proc/pid/net/ (since Linux 2.6.25)
              See the description of /proc/net.

       /proc/net/
              This directory contains various files and subdirectories
              containing information about the networking layer.  The
              files contain ASCII structures and are, therefore,
              readable with cat(1).  However, the standard netstat(8)
              suite provides much cleaner access to these files.

              With the advent of network namespaces, various information
              relating to the network stack is virtualized (see
              network_namespaces(7)).  Thus, since Linux 2.6.25,
              /proc/net is a symbolic link to the directory
              /proc/self/net, which contains the same files and
              directories as listed below.  However, these files and
              directories now expose information for the network
              namespace of which the process is a member.

       /proc/net/arp
              This holds an ASCII readable dump of the kernel ARP table
              used for address resolutions.  It will show both
              dynamically learned and preprogrammed ARP entries.  The
              format is:

                  IP address     HW type   Flags     HW address          Mask   Device
                  192.168.0.50   0x1       0x2       00:50:BF:25:68:F3   *      eth0
                  192.168.0.250  0x1       0xc       00:00:00:00:00:00   *      eth0

              Here "IP address" is the IPv4 address of the machine and
              the "HW type" is the hardware type of the address from
              RFC 826.  The flags are the internal flags of the ARP
              structure (as defined in /usr/include/linux/if_arp.h) and
              the "HW address" is the data link layer mapping for that
              IP address if it is known.

       /proc/net/dev
              The dev pseudo-file contains network device status
              information.  This gives the number of received and sent
              packets, the number of errors and collisions and other
              basic statistics.  These are used by the ifconfig(8)
              program to report device status.  The format is:

              Inter-|   Receive                                                |  Transmit
               face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
                  lo: 2776770   11307    0    0    0     0          0         0  2776770   11307    0    0    0     0       0          0
                eth0: 1215645    2751    0    0    0     0          0         0  1782404    4324    0    0    0   427       0          0
                ppp0: 1622270    5552    1    0    0     0          0         0   354130    5669    0    0    0     0       0          0
                tap0:    7714      81    0    0    0     0          0         0     7714      81    0    0    0     0       0          0

       /proc/net/dev_mcast
              Defined in /usr/src/linux/net/core/dev_mcast.c:

                  indx interface_name  dmi_u dmi_g dmi_address
                  2    eth0            1     0     01005e000001
                  3    eth1            1     0     01005e000001
                  4    eth2            1     0     01005e000001

       /proc/net/igmp
              Internet Group Management Protocol.  Defined in
              /usr/src/linux/net/core/igmp.c.

       /proc/net/rarp
              This file uses the same format as the arp file and
              contains the current reverse mapping database used to
              provide rarp(8) reverse address lookup services.  If RARP
              is not configured into the kernel, this file will not be
              present.

       /proc/net/raw
              Holds a dump of the RAW socket table.  Much of the
              information is not of use apart from debugging.  The "sl"
              value is the kernel hash slot for the socket, the
              "local_address" is the local address and protocol number
              pair.  "St" is the internal status of the socket.  The
              "tx_queue" and "rx_queue" are the outgoing and incoming
              data queue in terms of kernel memory usage.  The "tr",
              "tm->when", and "rexmits" fields are not used by RAW.  The
              "uid" field holds the effective UID of the creator of the
              socket.

       /proc/net/snmp
              This file holds the ASCII data needed for the IP, ICMP,
              TCP, and UDP management information bases for an SNMP
              agent.

       /proc/net/tcp
              Holds a dump of the TCP socket table.  Much of the
              information is not of use apart from debugging.  The "sl"
              value is the kernel hash slot for the socket, the
              "local_address" is the local address and port number pair.
              The "rem_address" is the remote address and port number
              pair (if connected).  "St" is the internal status of the
              socket.  The "tx_queue" and "rx_queue" are the outgoing
              and incoming data queue in terms of kernel memory usage.
              The "tr", "tm->when", and "rexmits" fields hold internal
              information of the kernel socket state and are useful only
              for debugging.  The "uid" field holds the effective UID of
              the creator of the socket.

       /proc/net/udp
              Holds a dump of the UDP socket table.  Much of the
              information is not of use apart from debugging.  The "sl"
              value is the kernel hash slot for the socket, the
              "local_address" is the local address and port number pair.
              The "rem_address" is the remote address and port number
              pair (if connected).  "St" is the internal status of the
              socket.  The "tx_queue" and "rx_queue" are the outgoing
              and incoming data queue in terms of kernel memory usage.
              The "tr", "tm->when", and "rexmits" fields are not used by
              UDP.  The "uid" field holds the effective UID of the
              creator of the socket.  The format is:

              sl  local_address rem_address   st tx_queue rx_queue tr rexmits  tm->when uid
               1: 01642C89:0201 0C642C89:03FF 01 00000000:00000001 01:000071BA 00000000 0
               1: 00000000:0801 00000000:0000 0A 00000000:00000000 00:00000000 6F000100 0
               1: 00000000:0201 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0

       /proc/net/unix
              Lists the UNIX domain sockets present within the system
              and their status.  The format is:

              Num RefCount Protocol Flags    Type St Inode Path
               0: 00000002 00000000 00000000 0001 03    42
               1: 00000001 00000000 00010000 0001 01  1948 /dev/printer

              The fields are as follows:

              Num:   the kernel table slot number.

              RefCount:
                     the number of users of the socket.

              Protocol:
                     currently always 0.

              Flags: the internal kernel flags holding the status of the
                     socket.

              Type:  the socket type.  For SOCK_STREAM sockets, this is
                     0001; for SOCK_DGRAM sockets, it is 0002; and for
                     SOCK_SEQPACKET sockets, it is 0005.

              St:    the internal state of the socket.

              Inode: the inode number of the socket.

              Path:  the bound pathname (if any) of the socket.  Sockets
                     in the abstract namespace are included in the list,
                     and are shown with a Path that commences with the
                     character '@'.

       /proc/net/netfilter/nfnetlink_queue
              This file contains information about netfilter user-space
              queueing, if used.  Each line represents a queue.  Queues
              that have not been subscribed to by user space are not
              shown.

                     1   4207     0  2 65535     0     0        0  1
                    (1)   (2)    (3)(4)  (5)    (6)   (7)      (8)

              The fields in each line are:

              (1)  The ID of the queue.  This matches what is specified
                   in the --queue-num or --queue-balance options to the
                   iptables(8) NFQUEUE target.  See
                   iptables-extensions(8) for more information.

              (2)  The netlink port ID subscribed to the queue.

              (3)  The number of packets currently queued and waiting to
                   be processed by the application.

              (4)  The copy mode of the queue.  It is either 1 (metadata
                   only) or 2 (also copy payload data to user space).

              (5)  Copy range; that is, how many bytes of packet payload
                   should be copied to user space at most.

              (6)  queue dropped.  Number of packets that had to be
                   dropped by the kernel because too many packets are
                   already waiting for user space to send back the
                   mandatory accept/drop verdicts.

              (7)  queue user dropped.  Number of packets that were
                   dropped within the netlink subsystem.  Such drops
                   usually happen when the corresponding socket buffer
                   is full; that is, user space is not able to read
                   messages fast enough.

              (8)  sequence number.  Every queued packet is associated
                   with a (32-bit) monotonically increasing sequence
                   number.  This shows the ID of the most recent packet
                   queued.

              The last number exists only for compatibility reasons and
              is always 1.

SEE ALSO         top

       proc(5)

COLOPHON         top

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Linux man-pages 6.9.1          2024-05-02                proc_pid_net(5)

Pages that refer to this page: proc_sys_net(5)