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The generic profile provides a starting point for investigating packets in the networking stack. It defines a wide set of probes in various places and enables automatic collector selection.

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What it enables

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Probes

The generic profile attaches probes at key points throughout the network stack: Receive path:
  • tp:net:netif_receive_skb - Packet reception at network interface
  • tp:net:netif_rx - Early packet reception
  • tp:net:napi_gro_receive_entry - GRO (Generic Receive Offload) entry
  • tp:net:napi_gro_frags_entry - GRO fragments entry
  • kprobe:arp_process - ARP packet processing
  • kprobe:ip_rcv / kprobe:ipv6_rcv - IPv4/IPv6 reception
Protocol handlers:
  • kprobe:tcp_v4_rcv / kprobe:tcp_v6_rcv - TCP reception
  • kprobe:tcp_gro_receive / kprobe:tcp6_gro_receive - TCP GRO
  • kprobe:tcp_rcv_established - TCP established state
  • kprobe:tcp_rcv_state_process - TCP state processing
  • kprobe:__tcp_retransmit_skb - TCP retransmissions
  • kprobe:udp_rcv / kprobe:udpv6_rcv - UDP reception
  • kprobe:udp_gro_receive / kprobe:udp6_gro_receive - UDP GRO
  • kprobe:icmp_rcv / kprobe:icmpv6_rcv - ICMP reception
Transmit path:
  • tp:net:net_dev_queue - Packet queuing
  • tp:net:net_dev_start_xmit - Packet transmission start
  • kprobe:ip_output / kprobe:ip6_output - IPv4/IPv6 output
  • kprobe:skb_scrub_packet - Packet scrubbing (namespace transitions)

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Collectors

The profile enables automatic collector selection, which typically includes:
  • skb - Socket buffer metadata
  • skb-drop - Drop reason information
  • skb-tracking - Packet tracking across the stack

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Usage

retis -p generic collect
The generic profile is ideal when you’re not sure where in the networking stack your issue might be occurring. It provides broad visibility across the entire path.

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Use cases

  • Initial investigation: Starting point when the root cause is unknown
  • Protocol debugging: Tracing packets through different protocol layers
  • Path analysis: Understanding the complete journey of a packet
  • Performance analysis: Identifying bottlenecks in the network stack

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Example output

The generic profile will capture events at multiple layers, showing how packets traverse the networking stack: 
7129250251406 (5) [ping] 23561 [tp] net:net_dev_start_xmit
  if 4 (wlp82s0) [redacted] > 2606:4700:4700::1111 ttl 64
  
7129262331018 (0) [irq/185-iwlwifi] 1259 [tp] net:netif_receive_skb
  if 4 (wlp82s0) 2606:4700:4700::1111 > [redacted] ttl 54

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