From 5c6dd17a373a2c56e57f02426d66a79af7faa19c Mon Sep 17 00:00:00 2001 From: Neale Ranns Date: Thu, 17 Feb 2022 09:08:47 +0000 Subject: ip: rate-limit the sending of ICMP error messages Type: improvement For error conditions, such as TTL expired, dest unreach, etc, Rate limit the sending of ICMP error messages. The rate limiting is done based on src,dst IP address of the received packet. the rate limit has been chosen, somewhat arbitrarily, to be 1e-3. This is the same limit as the ARP throttling. Signed-off-by: Neale Ranns Change-Id: I4a0b791cde8c941a9bf37de6aa5da56779d3cef4 --- src/vnet/ip/icmp4.c | 30 +++++++++++++++++++++++++++++- src/vnet/ip/icmp6.c | 30 +++++++++++++++++++++++++++++- 2 files changed, 58 insertions(+), 2 deletions(-) (limited to 'src/vnet') diff --git a/src/vnet/ip/icmp4.c b/src/vnet/ip/icmp4.c index 5f9ffa3b2b7..857c3b1d2a5 100644 --- a/src/vnet/ip/icmp4.c +++ b/src/vnet/ip/icmp4.c @@ -41,6 +41,7 @@ #include #include #include +#include static char *icmp_error_strings[] = { #define _(f,s) s, @@ -48,6 +49,9 @@ static char *icmp_error_strings[] = { #undef _ }; +/** ICMP throttling */ +static throttle_t icmp_throttle; + static u8 * format_ip4_icmp_type_and_code (u8 * s, va_list * args) { @@ -255,11 +259,14 @@ ip4_icmp_error (vlib_main_t * vm, u32 *from, *to_next; uword n_left_from, n_left_to_next; ip4_icmp_error_next_t next_index; + u32 thread_index = vm->thread_index; from = vlib_frame_vector_args (frame); n_left_from = frame->n_vectors; next_index = node->cached_next_index; + u64 seed = throttle_seed (&icmp_throttle, thread_index, vlib_time_now (vm)); + if (node->flags & VLIB_NODE_FLAG_TRACE) vlib_trace_frame_buffers_only (vm, node, from, frame->n_vectors, /* stride */ 1, @@ -289,6 +296,21 @@ ip4_icmp_error (vlib_main_t * vm, ip_csum_t sum; org_p0 = vlib_get_buffer (vm, org_pi0); + ip0 = vlib_buffer_get_current (org_p0); + + /* Rate limit based on the src,dst addresses in the original packet + */ + u64 r0 = + (u64) ip0->dst_address.as_u32 << 32 | ip0->src_address.as_u32; + + if (throttle_check (&icmp_throttle, thread_index, r0, seed)) + { + vlib_error_count (vm, node->node_index, ICMP4_ERROR_DROP, 1); + from += 1; + n_left_from -= 1; + continue; + } + p0 = vlib_buffer_copy_no_chain (vm, org_p0, &pi0); if (!p0 || pi0 == ~0) /* Out of buffers */ continue; @@ -300,9 +322,10 @@ ip4_icmp_error (vlib_main_t * vm, n_left_from -= 1; n_left_to_next -= 1; - ip0 = vlib_buffer_get_current (p0); sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX]; + vlib_buffer_copy_trace_flag (vm, p0, pi0); + /* Add IP header and ICMPv4 header including a 4 byte data field */ vlib_buffer_advance (p0, -sizeof (ip4_header_t) - @@ -570,6 +593,11 @@ icmp4_init (vlib_main_t * vm) ICMP_INPUT_NEXT_ERROR, sizeof (cm->ip4_input_next_index_by_type)); + vlib_thread_main_t *tm = &vlib_thread_main; + u32 n_vlib_mains = tm->n_vlib_mains; + + throttle_init (&icmp_throttle, n_vlib_mains, 1e-3); + return 0; } diff --git a/src/vnet/ip/icmp6.c b/src/vnet/ip/icmp6.c index 3c8300ff014..f92f31c05cb 100644 --- a/src/vnet/ip/icmp6.c +++ b/src/vnet/ip/icmp6.c @@ -41,6 +41,10 @@ #include #include #include +#include + +/** ICMP throttling */ +static throttle_t icmp_throttle; static u8 * format_ip6_icmp_type_and_code (u8 * s, va_list * args) @@ -296,11 +300,14 @@ ip6_icmp_error (vlib_main_t * vm, u32 *from, *to_next; uword n_left_from, n_left_to_next; ip6_icmp_error_next_t next_index; + u32 thread_index = vm->thread_index; from = vlib_frame_vector_args (frame); n_left_from = frame->n_vectors; next_index = node->cached_next_index; + u64 seed = throttle_seed (&icmp_throttle, thread_index, vlib_time_now (vm)); + if (node->flags & VLIB_NODE_FLAG_TRACE) vlib_trace_frame_buffers_only (vm, node, from, frame->n_vectors, /* stride */ 1, @@ -330,6 +337,21 @@ ip6_icmp_error (vlib_main_t * vm, int bogus_length; org_p0 = vlib_get_buffer (vm, org_pi0); + ip0 = vlib_buffer_get_current (org_p0); + + /* Rate limit based on the src,dst addresses in the original packet + */ + u64 r0 = (ip6_address_hash_to_u64 (&ip0->dst_address) ^ + ip6_address_hash_to_u64 (&ip0->src_address)); + + if (throttle_check (&icmp_throttle, thread_index, r0, seed)) + { + vlib_error_count (vm, node->node_index, ICMP4_ERROR_DROP, 1); + from += 1; + n_left_from -= 1; + continue; + } + p0 = vlib_buffer_copy_no_chain (vm, org_p0, &pi0); if (!p0 || pi0 == ~0) /* Out of buffers */ continue; @@ -341,9 +363,10 @@ ip6_icmp_error (vlib_main_t * vm, n_left_from -= 1; n_left_to_next -= 1; - ip0 = vlib_buffer_get_current (p0); sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX]; + vlib_buffer_copy_trace_flag (vm, p0, pi0); + /* Add IP header and ICMPv6 header including a 4 byte data field */ vlib_buffer_advance (p0, -(sizeof (ip6_header_t) + @@ -624,6 +647,11 @@ icmp6_init (vlib_main_t * vm) cm->min_valid_length_by_type[ICMP6_redirect] = sizeof (icmp6_redirect_header_t); + vlib_thread_main_t *tm = &vlib_thread_main; + u32 n_vlib_mains = tm->n_vlib_mains; + + throttle_init (&icmp_throttle, n_vlib_mains, 1e-3); + return (NULL); } -- cgit 1.2.3-korg