From ffd78d1ef8fe80d1b756a71d42d5eadda60ae996 Mon Sep 17 00:00:00 2001 From: Neale Ranns Date: Fri, 9 Feb 2018 06:05:16 -0800 Subject: [PATCH] Improve MTU handling - setting MTU on an interface updates the L3 max bytes too - value cached in the adjacency is also updated - MTU exceeded generates ICMP to sender Change-Id: I343ec71d8e903b529594c4bd0543f04bc7f370b3 Signed-off-by: Neale Ranns --- src/vnet/adj/adj.c | 37 +++++++++++++++++++++++++++++++++++++ src/vnet/adj/adj.h | 6 ++++++ src/vnet/adj/rewrite.c | 12 +++++++++--- src/vnet/adj/rewrite.h | 3 +++ src/vnet/interface.c | 16 ++++++++++++++++ src/vnet/interface_api.c | 7 +------ src/vnet/interface_cli.c | 7 +------ src/vnet/interface_funcs.h | 3 +++ src/vnet/ip/ip4_forward.c | 43 ++++++++++++++++++++++++++++++------------- test/test_ip4.py | 26 ++++++++++++++++++++++++++ test/vpp_papi_provider.py | 10 ++++++++++ 11 files changed, 142 insertions(+), 28 deletions(-) diff --git a/src/vnet/adj/adj.c b/src/vnet/adj/adj.c index 5f7fe74cd43..d28d5195330 100644 --- a/src/vnet/adj/adj.c +++ b/src/vnet/adj/adj.c @@ -338,6 +338,43 @@ adj_feature_update (u32 sw_if_index, adj_walk (sw_if_index, adj_feature_update_walk_cb, &ctx); } +static adj_walk_rc_t +adj_mtu_update_walk_cb (adj_index_t ai, + void *arg) +{ + ip_adjacency_t *adj; + + adj = adj_get(ai); + + vnet_rewrite_update_mtu (vnet_get_main(), + &adj->rewrite_header); + + return (ADJ_WALK_RC_CONTINUE); +} + +static void +adj_sw_mtu_update (vnet_main_t * vnm, + u32 sw_if_index, + void *ctx) +{ + /* + * Walk all the adjacencies on the interface to update the cached MTU + */ + adj_walk (sw_if_index, adj_mtu_update_walk_cb, NULL); +} + +void +adj_mtu_update (u32 hw_if_index) +{ + /* + * Walk all the SW interfaces on the HW interface to update the cached MTU + */ + vnet_hw_interface_walk_sw(vnet_get_main(), + hw_if_index, + adj_sw_mtu_update, + NULL); +} + /** * @brief Walk the Adjacencies on a given interface */ diff --git a/src/vnet/adj/adj.h b/src/vnet/adj/adj.h index fe77d1634e0..bcf6c041209 100644 --- a/src/vnet/adj/adj.h +++ b/src/vnet/adj/adj.h @@ -344,6 +344,12 @@ extern const u8* adj_get_rewrite (adj_index_t ai); */ extern void adj_feature_update (u32 sw_if_index, u8 arc_index, u8 is_enable); +/** + * @brief Notify the adjacency subsystem that the MTU settings for + * an HW interface have changed + */ +extern void adj_mtu_update (u32 hw_if_index); + /** * @brief * The global adjacnecy pool. Exposed for fast/inline data-plane access diff --git a/src/vnet/adj/rewrite.c b/src/vnet/adj/rewrite.c index 9150f2c6c37..c21495a9644 100644 --- a/src/vnet/adj/rewrite.c +++ b/src/vnet/adj/rewrite.c @@ -77,15 +77,14 @@ format_vnet_rewrite (u8 * s, va_list * args) vnet_sw_interface_t *si; si = vnet_get_sw_interface_safe (vnm, rw->sw_if_index); if (NULL != si) - s = format (s, "%U: ", format_vnet_sw_interface_name, vnm, si); + s = format (s, "%U:", format_vnet_sw_interface_name, vnm, si); else s = format (s, "DELETED:%d", rw->sw_if_index); } /* Format rewrite string. */ if (rw->data_bytes > 0) - - s = format (s, "%U", + s = format (s, " %U", format_hex_bytes, rw->data + max_data_bytes - rw->data_bytes, rw->data_bytes); @@ -110,6 +109,13 @@ vnet_rewrite_init (vnet_main_t * vnm, vnet_sw_interface_get_mtu (vnm, sw_if_index, VLIB_TX); } +void +vnet_rewrite_update_mtu (vnet_main_t * vnm, vnet_rewrite_header_t * rw) +{ + rw->max_l3_packet_bytes = + vnet_sw_interface_get_mtu (vnm, rw->sw_if_index, VLIB_TX); +} + void vnet_rewrite_for_sw_interface (vnet_main_t * vnm, vnet_link_t link_type, diff --git a/src/vnet/adj/rewrite.h b/src/vnet/adj/rewrite.h index 1dea72f5ed8..005ac41fe72 100644 --- a/src/vnet/adj/rewrite.h +++ b/src/vnet/adj/rewrite.h @@ -328,6 +328,9 @@ void vnet_rewrite_init (struct vnet_main_t *vnm, u32 this_node, u32 next_node, vnet_rewrite_header_t * rw); +void vnet_rewrite_update_mtu (struct vnet_main_t *vnm, + vnet_rewrite_header_t * rw); + u8 *vnet_build_rewrite_for_sw_interface (struct vnet_main_t *vnm, u32 sw_if_index, vnet_link_t packet_type, diff --git a/src/vnet/interface.c b/src/vnet/interface.c index a34bb7931ae..7516aec0e71 100644 --- a/src/vnet/interface.c +++ b/src/vnet/interface.c @@ -122,6 +122,22 @@ unserialize_vnet_sw_interface_set_flags (serialize_main_t * m, va_list * va) /* helper_flags no redistribution */ 0); } +void +vnet_hw_interface_set_mtu (vnet_main_t * vnm, u32 hw_if_index, u32 mtu) +{ + vnet_hw_interface_t *hi = vnet_get_hw_interface (vnm, hw_if_index); + + if (hi->max_packet_bytes != mtu) + { + u16 l3_pad = hi->max_packet_bytes - hi->max_l3_packet_bytes[VLIB_TX]; + hi->max_packet_bytes = mtu; + hi->max_l3_packet_bytes[VLIB_TX] = + hi->max_l3_packet_bytes[VLIB_RX] = mtu - l3_pad; + ethernet_set_flags (vnm, hw_if_index, ETHERNET_INTERFACE_FLAG_MTU); + adj_mtu_update (hw_if_index); + } +} + static void unserialize_vnet_hw_interface_set_flags (serialize_main_t * m, va_list * va) { diff --git a/src/vnet/interface_api.c b/src/vnet/interface_api.c index 0541f311bc2..ed116bc88d9 100644 --- a/src/vnet/interface_api.c +++ b/src/vnet/interface_api.c @@ -98,7 +98,6 @@ vl_api_sw_interface_set_mtu_t_handler (vl_api_sw_interface_set_mtu_t * mp) { vl_api_sw_interface_set_mtu_reply_t *rmp; vnet_main_t *vnm = vnet_get_main (); - u32 flags = ETHERNET_INTERFACE_FLAG_MTU; u32 sw_if_index = ntohl (mp->sw_if_index); u16 mtu = ntohs (mp->mtu); ethernet_main_t *em = ðernet_main; @@ -134,11 +133,7 @@ vl_api_sw_interface_set_mtu_t_handler (vl_api_sw_interface_set_mtu_t * mp) goto bad_sw_if_index; } - if (hi->max_packet_bytes != mtu) - { - hi->max_packet_bytes = mtu; - ethernet_set_flags (vnm, si->hw_if_index, flags); - } + vnet_hw_interface_set_mtu (vnm, si->hw_if_index, mtu); BAD_SW_IF_INDEX_LABEL; REPLY_MACRO (VL_API_SW_INTERFACE_SET_MTU_REPLY); diff --git a/src/vnet/interface_cli.c b/src/vnet/interface_cli.c index 5509e3ffa57..8880d9749b8 100644 --- a/src/vnet/interface_cli.c +++ b/src/vnet/interface_cli.c @@ -1132,7 +1132,6 @@ mtu_cmd (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd) { vnet_main_t *vnm = vnet_get_main (); u32 hw_if_index, mtu; - u32 flags = ETHERNET_INTERFACE_FLAG_MTU; ethernet_main_t *em = ðernet_main; if (unformat (input, "%d %U", &mtu, @@ -1153,11 +1152,7 @@ mtu_cmd (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd) return clib_error_return (0, "Invalid mtu (%d): must be <= (%d)", mtu, hi->max_supported_packet_bytes); - if (hi->max_packet_bytes != mtu) - { - hi->max_packet_bytes = mtu; - ethernet_set_flags (vnm, hw_if_index, flags); - } + vnet_hw_interface_set_mtu (vnm, hw_if_index, mtu); } else return clib_error_return (0, "unknown input `%U'", diff --git a/src/vnet/interface_funcs.h b/src/vnet/interface_funcs.h index ac50e7cd6ca..5aecaff9b27 100644 --- a/src/vnet/interface_funcs.h +++ b/src/vnet/interface_funcs.h @@ -292,6 +292,9 @@ clib_error_t *set_hw_interface_change_rx_mode (vnet_main_t * vnm, vnet_hw_interface_rx_mode mode); +/* Set the MTU on the HW interface */ +void vnet_hw_interface_set_mtu (vnet_main_t * vnm, u32 hw_if_index, u32 mtu); + /* Formats sw/hw interface. */ format_function_t format_vnet_hw_interface; format_function_t format_vnet_hw_interface_rx_mode; diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c index ae4510626d0..b9875d72b8e 100644 --- a/src/vnet/ip/ip4_forward.c +++ b/src/vnet/ip/ip4_forward.c @@ -2109,16 +2109,26 @@ ip4_rewrite_inline (vlib_main_t * vm, vnet_buffer (p1)->ip.save_rewrite_length = rw_len1; /* Check MTU of outgoing interface. */ - error0 = - (vlib_buffer_length_in_chain (vm, p0) > - adj0[0]. - rewrite_header.max_l3_packet_bytes ? IP4_ERROR_MTU_EXCEEDED : - error0); - error1 = - (vlib_buffer_length_in_chain (vm, p1) > - adj1[0]. - rewrite_header.max_l3_packet_bytes ? IP4_ERROR_MTU_EXCEEDED : - error1); + if (vlib_buffer_length_in_chain (vm, p0) > + adj0[0].rewrite_header.max_l3_packet_bytes) + { + error0 = IP4_ERROR_MTU_EXCEEDED; + next0 = IP4_REWRITE_NEXT_ICMP_ERROR; + icmp4_error_set_vnet_buffer + (p0, ICMP4_destination_unreachable, + ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set, + 0); + } + if (vlib_buffer_length_in_chain (vm, p1) > + adj1[0].rewrite_header.max_l3_packet_bytes) + { + error1 = IP4_ERROR_MTU_EXCEEDED; + next1 = IP4_REWRITE_NEXT_ICMP_ERROR; + icmp4_error_set_vnet_buffer + (p1, ICMP4_destination_unreachable, + ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set, + 0); + } if (is_mcast) { @@ -2290,9 +2300,16 @@ ip4_rewrite_inline (vlib_main_t * vm, vlib_buffer_length_in_chain (vm, p0) + rw_len0); /* Check MTU of outgoing interface. */ - error0 = (vlib_buffer_length_in_chain (vm, p0) - > adj0[0].rewrite_header.max_l3_packet_bytes - ? IP4_ERROR_MTU_EXCEEDED : error0); + if (vlib_buffer_length_in_chain (vm, p0) > + adj0[0].rewrite_header.max_l3_packet_bytes) + { + error0 = IP4_ERROR_MTU_EXCEEDED; + next0 = IP4_REWRITE_NEXT_ICMP_ERROR; + icmp4_error_set_vnet_buffer + (p0, ICMP4_destination_unreachable, + ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set, + 0); + } if (is_mcast) { error0 = ((adj0[0].rewrite_header.sw_if_index == diff --git a/test/test_ip4.py b/test/test_ip4.py index 79d4a36285c..1a611251eb5 100644 --- a/test/test_ip4.py +++ b/test/test_ip4.py @@ -1287,6 +1287,32 @@ class TestIPInput(VppTestCase): self.assertEqual(icmp.src, self.pg0.remote_ip4) self.assertEqual(icmp.dst, self.pg1.remote_ip4) + # + # MTU exceeded + # + p_mtu = (Ether(src=self.pg0.remote_mac, + dst=self.pg0.local_mac) / + IP(src=self.pg0.remote_ip4, + dst=self.pg1.remote_ip4, + ttl=10) / + UDP(sport=1234, dport=1234) / + Raw('\xa5' * 2000)) + + self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, 1500) + + rx = self.send_and_expect(self.pg0, p_mtu * 65, self.pg0) + rx = rx[0] + icmp = rx[ICMP] + + self.assertEqual(icmptypes[icmp.type], "dest-unreach") + self.assertEqual(icmpcodes[icmp.type][icmp.code], + "fragmentation-needed") + self.assertEqual(icmp.src, self.pg0.remote_ip4) + self.assertEqual(icmp.dst, self.pg1.remote_ip4) + + self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, 2500) + rx = self.send_and_expect(self.pg0, p_mtu * 65, self.pg1) + if __name__ == '__main__': unittest.main(testRunner=VppTestRunner) diff --git a/test/vpp_papi_provider.py b/test/vpp_papi_provider.py index 15a566c5bc7..b7c76530307 100644 --- a/test/vpp_papi_provider.py +++ b/test/vpp_papi_provider.py @@ -629,6 +629,16 @@ class VppPapiProvider(object): {'sw_if_index': sw_if_index, 'admin_up_down': admin_up_down}) + def sw_interface_set_mtu(self, sw_if_index, mtu): + """ + :param sw_if_index: + :param mtu: + + """ + return self.api(self.papi.sw_interface_set_mtu, + {'sw_if_index': sw_if_index, + 'mtu': mtu}) + def create_subif(self, sw_if_index, sub_id, outer_vlan, inner_vlan, no_tags=0, one_tag=0, two_tags=0, dot1ad=0, exact_match=0, default_sub=0, outer_vlan_id_any=0, inner_vlan_id_any=0): -- 2.16.6