From 4330c46abb78882fc453b1b682ac4f12a22b5e68 Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Wed, 10 Jun 2020 17:07:32 -0400 Subject: interface: add minimal vpp pkt trace for error-drop Provide a minimal trace [ip4/ip6 src/dst address] for dropped pkts when the user specifies "trace add error-drop XXXX", but does not trace pkts from the original input node. This is a wireshark dissector problem. Packets thrown at error-drop may be well-formed, or not. VPP must not crash, no matter what. The minimal trace capture and decode could be enhanced. Anyone interested in doing that must consider all of the corner-cases involved. This version should be at least somewhat useful. Note that "pcap trace drop ..." - and the packet generator - seem like the right tools to use when researching more complex issues. Type: improvement Signed-off-by: Dave Barach Change-Id: I961ca133980ffa2a1e5707879a443b21442ed894 --- src/vnet/interface_cli.c | 2 +- src/vnet/interface_output.c | 131 +++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 125 insertions(+), 8 deletions(-) (limited to 'src/vnet') diff --git a/src/vnet/interface_cli.c b/src/vnet/interface_cli.c index 2e5714c3c0f..569e2eb6c54 100644 --- a/src/vnet/interface_cli.c +++ b/src/vnet/interface_cli.c @@ -2046,7 +2046,7 @@ pcap_trace_command_fn (vlib_main_t * vm, int drop_enable = 0; int status = 0; int filter = 0; - u32 sw_if_index = ~0; + u32 sw_if_index = 0; /* default: any interface */ /* Get a line of input. */ if (!unformat_user (input, unformat_line_input, line_input)) diff --git a/src/vnet/interface_output.c b/src/vnet/interface_output.c index f9490f34f6a..cb13f5361aa 100644 --- a/src/vnet/interface_output.c +++ b/src/vnet/interface_output.c @@ -39,6 +39,7 @@ #include #include +#include #include #include #include @@ -603,9 +604,13 @@ VLIB_NODE_FN (vnet_per_buffer_interface_output_node) (vlib_main_t * vm, typedef struct vnet_error_trace_t_ { u32 sw_if_index; + i8 details_valid; + u8 is_ip6; + u8 pad[2]; + u16 mactype; + ip46_address_t src, dst; } vnet_error_trace_t; - static u8 * format_vnet_error_trace (u8 * s, va_list * va) { @@ -613,9 +618,29 @@ format_vnet_error_trace (u8 * s, va_list * va) CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *); vnet_error_trace_t *t = va_arg (*va, vnet_error_trace_t *); - s = format (s, "rx:%U", format_vnet_sw_if_index_name, - vnet_get_main (), t->sw_if_index); - + /* Normal, non-catchup trace */ + if (t->details_valid == 0) + { + s = format (s, "rx:%U", format_vnet_sw_if_index_name, + vnet_get_main (), t->sw_if_index); + } + else if (t->details_valid == 1) + { + /* The trace capture code didn't understant the mactype */ + s = format (s, "mactype 0x%4x (not decoded)", t->mactype); + } + else if (t->details_valid == 2) + { + /* Dump the src/dst addresses */ + if (t->is_ip6 == 0) + s = format (s, "IP4: %U -> %U", + format_ip4_address, &t->src.ip4, + format_ip4_address, &t->dst.ip4); + else + s = format (s, "IP6: %U -> %U", + format_ip6_address, &t->src.ip6, + format_ip6_address, &t->dst.ip6); + } return s; } @@ -646,13 +671,17 @@ interface_trace_buffers (vlib_main_t * vm, if (b0->flags & VLIB_BUFFER_IS_TRACED) { - t0 = vlib_add_trace (vm, node, b0, sizeof (t0[0])); + t0 = vlib_add_trace (vm, node, b0, + STRUCT_OFFSET_OF (vnet_error_trace_t, pad)); t0->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX]; + t0->details_valid = 0; } if (b1->flags & VLIB_BUFFER_IS_TRACED) { - t1 = vlib_add_trace (vm, node, b1, sizeof (t1[0])); + t1 = vlib_add_trace (vm, node, b1, + STRUCT_OFFSET_OF (vnet_error_trace_t, pad)); t1->sw_if_index = vnet_buffer (b1)->sw_if_index[VLIB_RX]; + t1->details_valid = 0; } buffers += 2; n_left -= 2; @@ -670,8 +699,10 @@ interface_trace_buffers (vlib_main_t * vm, if (b0->flags & VLIB_BUFFER_IS_TRACED) { - t0 = vlib_add_trace (vm, node, b0, sizeof (t0[0])); + t0 = vlib_add_trace (vm, node, b0, + STRUCT_OFFSET_OF (vnet_error_trace_t, pad)); t0->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX]; + t0->details_valid = 0; } buffers += 1; n_left -= 1; @@ -685,6 +716,56 @@ typedef enum VNET_ERROR_N_DISPOSITION, } vnet_error_disposition_t; +static void +drop_catchup_trace (vlib_main_t * vm, + vlib_node_runtime_t * node, vlib_buffer_t * b) +{ + /* Can we safely rewind the buffer? If not, fagedaboudit */ + if (b->flags & VNET_BUFFER_F_L2_HDR_OFFSET_VALID) + { + vnet_error_trace_t *t; + ip4_header_t *ip4; + ip6_header_t *ip6; + ethernet_header_t *eh; + i16 delta; + + t = vlib_add_trace (vm, node, b, sizeof (*t)); + delta = vnet_buffer (b)->l2_hdr_offset - b->current_data; + vlib_buffer_advance (b, delta); + + eh = vlib_buffer_get_current (b); + /* Save mactype */ + t->mactype = clib_net_to_host_u16 (eh->type); + t->details_valid = 1; + switch (t->mactype) + { + case ETHERNET_TYPE_IP4: + ip4 = (void *) (eh + 1); + t->details_valid = 2; + t->is_ip6 = 0; + t->src.ip4.as_u32 = ip4->src_address.as_u32; + t->dst.ip4.as_u32 = ip4->dst_address.as_u32; + break; + + case ETHERNET_TYPE_IP6: + ip6 = (void *) (eh + 1); + t->details_valid = 2; + t->is_ip6 = 1; + clib_memcpy_fast (t->src.as_u8, ip6->src_address.as_u8, + sizeof (ip6_address_t)); + clib_memcpy_fast (t->dst.as_u8, ip6->dst_address.as_u8, + sizeof (ip6_address_t)); + break; + + default: + /* Dunno, do nothing, leave details_valid alone */ + break; + } + /* Restore current data (probably unnecessary) */ + vlib_buffer_advance (b, -delta); + } +} + static_always_inline uword interface_drop_punt (vlib_main_t * vm, vlib_node_runtime_t * node, @@ -696,6 +777,7 @@ interface_drop_punt (vlib_main_t * vm, u32 sw_if_indices[VLIB_FRAME_SIZE]; vlib_simple_counter_main_t *cm; u16 nexts[VLIB_FRAME_SIZE]; + u32 n_trace; vnet_main_t *vnm; vnm = vnet_get_main (); @@ -707,6 +789,39 @@ interface_drop_punt (vlib_main_t * vm, vlib_get_buffers (vm, from, bufs, n_left); + /* "trace add error-drop NNN?" */ + if (PREDICT_FALSE ((n_trace = vlib_get_trace_count (vm, node)))) + { + /* If pkts aren't otherwise traced... */ + if ((node->flags & VLIB_NODE_FLAG_TRACE) == 0) + { + /* Trace them from here */ + node->flags |= VLIB_NODE_FLAG_TRACE; + while (n_trace && n_left) + { + vlib_trace_buffer (vm, node, 0 /* next_index */ , + b[0], 0 /* follow chain */ ); + /* + * Here we have a wireshark dissector problem. + * Packets may be well-formed, or not. We + * must not blow chunks in any case. + * + * Try to produce trace records which will help + * folks understand what's going on. + */ + drop_catchup_trace (vm, node, b[0]); + + n_trace--; + n_left--; + b++; + } + } + + vlib_set_trace_count (vm, node, n_trace); + b = bufs; + n_left = frame->n_vectors; + } + if (node->flags & VLIB_NODE_FLAG_TRACE) interface_trace_buffers (vm, node, frame); @@ -947,6 +1062,7 @@ VLIB_REGISTER_NODE (interface_drop) = { .name = "error-drop", .vector_size = sizeof (u32), .format_trace = format_vnet_error_trace, + .flags = VLIB_NODE_FLAG_TRACE_SUPPORTED, .n_next_nodes = 1, .next_nodes = { [0] = "drop", @@ -959,6 +1075,7 @@ VLIB_REGISTER_NODE (interface_punt) = { .name = "error-punt", .vector_size = sizeof (u32), .format_trace = format_vnet_error_trace, + .flags = VLIB_NODE_FLAG_TRACE_SUPPORTED, .n_next_nodes = 1, .next_nodes = { [0] = "punt", -- cgit 1.2.3-korg