From 6d5bfb69f15653bc7032e9a8ffe4b0cecba9971c Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Tue, 23 Aug 2016 15:23:10 -0400 Subject: [PATCH] VPP-346 Document the ip feature registration scheme Change-Id: I81a9e963bdeb437ca228f11aaedca8d122be7471 Signed-off-by: Dave Barach --- vnet/vnet/ip/ip_feature_registration.c | 387 +++++++++++++++++++++------------ vnet/vnet/ip/ip_feature_registration.h | 42 ++-- 2 files changed, 275 insertions(+), 154 deletions(-) diff --git a/vnet/vnet/ip/ip_feature_registration.c b/vnet/vnet/ip/ip_feature_registration.c index 72deee41004..baf7ea27729 100644 --- a/vnet/vnet/ip/ip_feature_registration.c +++ b/vnet/vnet/ip/ip_feature_registration.c @@ -16,7 +16,100 @@ #include #include -static int comma_split (u8 *s, u8 **a, u8 **b) +/** \file + + Dynamically compute IP feature subgraph ordering by performing a + topological sort across a set of "feature A before feature B" and + "feature C after feature B" constraints. + + Use the topological sort result to set up vnet_config_main_t's for + use at runtime. + + Feature subgraph arcs are simple enough. They start at specific + fixed nodes, and end at specific fixed nodes. In between, a + per-interface current feature configuration dictates which + additional nodes each packet visits. Each so-called feature node + can [of course] drop any specific packet. + + See ip4_forward.c, ip6_forward.c in this directory to see the + current rx-unicast, rx-multicast, and tx feature subgraph arc + definitions. + + Let's say that we wish to add a new feature to the ip4 unicast + feature subgraph arc, which needs to run before @c ip4-lookup. In + either base code or a plugin, + 
+    #include 
+
+ + and add the new feature as shown: + + 
+    VNET_IP4_UNICAST_FEATURE_INIT (ip4_lookup, static) =
+    {
+      .node_name = "my-ip4-unicast-feature",
+      .runs_before = ORDER_CONSTRAINTS {"ip4-lookup", 0}
+      .feature_index = &my_feature_index,
+    };
+
+ + Here's the standard coding pattern to enable / disable + @c my-ip4-unicast-feature on an interface: + + 
+    ip4_main_t *im = &ip4_main;
+    ip_lookup_main_t *lm = &im->lookup_main;
+    ip_config_main_t *rx_cm =
+        &lm->feature_config_mains[VNET_IP_RX_UNICAST_FEAT];
+
+    sw_if_index = 
+    ci = rx_cm->config_index_by_sw_if_index[sw_if_index];
+    ci = (is_add
+          ? vnet_config_add_feature
+          : vnet_config_del_feature)
+      (vm, &rx_cm->config_main,
+       ci,
+       my_feature_index,
+       0 / * &config struct if feature uses private config data * /,
+       0 / * sizeof config struct if feature uses private config data * /);
+    rx_cm->config_index_by_sw_if_index[sw_if_index] = ci;
+
+ + For tx features, add this line after setting + 
+    tx_cm->config_index_by_sw_if_index = ci.
+
+ + This maintains a + per-interface "at least one TX feature enabled" bitmap: + + 
+    vnet_config_update_tx_feature_count (lm, tx_cm, sw_if_index, is_add);
+
+ + Here's how to obtain the correct next node index in packet + processing code, aka in the implementation of @c my-ip4-unicast-feature: + + 
+    ip_lookup_main_t * lm = sm->ip4_lookup_main;
+    ip_config_main_t * cm = &lm->feature_config_mains[VNET_IP_RX_UNICAST_FEAT];
+
+    Call @c vnet_get_config_data to set next0, and to advance
+    @c b0->current_config_index:
+
+    config_data0 = vnet_get_config_data (&cm->config_main,
+                                         &b0->current_config_index,
+                                         &next0,
+                                         0 / * sizeof config data * /);
+
+ + Nodes are free to drop or otherwise redirect packets. Packets + which "pass" should be enqueued via the next0 arc computed by + vnet_get_config_data. +*/ + +static int +comma_split (u8 * s, u8 ** a, u8 ** b) { *a = s; @@ -28,41 +121,40 @@ static int comma_split (u8 *s, u8 **a, u8 **b) else return 1; - *b = (u8 *) (s+1); + *b = (u8 *) (s + 1); return 0; } clib_error_t * ip_feature_init_cast (vlib_main_t * vm, - ip_config_main_t * cm, - vnet_config_main_t * vcm, - char **feature_start_nodes, - int num_feature_start_nodes, - vnet_cast_t cast, - int is_ip4) + ip_config_main_t * cm, + vnet_config_main_t * vcm, + char **feature_start_nodes, + int num_feature_start_nodes, + vnet_cast_t cast, int is_ip4) { - uword * index_by_name; - uword * reg_by_index; - u8 ** node_names = 0; - u8 * node_name; - char ** these_constraints; - char * this_constraint_c; - u8 ** constraints = 0; - u8 * constraint_tuple; - u8 * this_constraint; - u8 ** orig, ** closure; - uword * p; + uword *index_by_name; + uword *reg_by_index; + u8 **node_names = 0; + u8 *node_name; + char **these_constraints; + char *this_constraint_c; + u8 **constraints = 0; + u8 *constraint_tuple; + u8 *this_constraint; + u8 **orig, **closure; + uword *p; int i, j, k; - u8 * a_name, * b_name; + u8 *a_name, *b_name; int a_index, b_index; int n_features; - u32 * result = 0; - vnet_ip_feature_registration_t * this_reg, * first_reg = 0; - char ** feature_nodes = 0; - hash_pair_t * hp; - u8 ** keys_to_delete = 0; - ip4_main_t * im4 = &ip4_main; - ip6_main_t * im6 = &ip6_main; + u32 *result = 0; + vnet_ip_feature_registration_t *this_reg, *first_reg = 0; + char **feature_nodes = 0; + hash_pair_t *hp; + u8 **keys_to_delete = 0; + ip4_main_t *im4 = &ip4_main; + ip6_main_t *im6 = &ip6_main; index_by_name = hash_create_string (0, sizeof (uword)); reg_by_index = hash_create (0, sizeof (uword)); @@ -70,60 +162,59 @@ ip_feature_init_cast (vlib_main_t * vm, if (cast == VNET_IP_RX_UNICAST_FEAT) { if (is_ip4) - first_reg = im4->next_uc_feature; + first_reg = im4->next_uc_feature; else - first_reg = im6->next_uc_feature; + first_reg = im6->next_uc_feature; } else if (cast == VNET_IP_RX_MULTICAST_FEAT) { if (is_ip4) - first_reg = im4->next_mc_feature; + first_reg = im4->next_mc_feature; else - first_reg = im6->next_mc_feature; - } + first_reg = im6->next_mc_feature; + } else if (cast == VNET_IP_TX_FEAT) { if (is_ip4) - first_reg = im4->next_tx_feature; + first_reg = im4->next_tx_feature; else - first_reg = im6->next_tx_feature; + first_reg = im6->next_tx_feature; } - + this_reg = first_reg; /* pass 1, collect feature node names, construct a before b pairs */ while (this_reg) { node_name = format (0, "%s%c", this_reg->node_name, 0); - hash_set (reg_by_index, vec_len(node_names), (uword) this_reg); + hash_set (reg_by_index, vec_len (node_names), (uword) this_reg); - hash_set_mem (index_by_name, node_name, vec_len(node_names)); + hash_set_mem (index_by_name, node_name, vec_len (node_names)); vec_add1 (node_names, node_name); these_constraints = this_reg->runs_before; - while (these_constraints && these_constraints [0]) - { - this_constraint_c = these_constraints[0]; + while (these_constraints && these_constraints[0]) + { + this_constraint_c = these_constraints[0]; - constraint_tuple = format (0, "%s,%s%c", node_name, - this_constraint_c, 0); - vec_add1 (constraints, constraint_tuple); - these_constraints++; - } + constraint_tuple = format (0, "%s,%s%c", node_name, + this_constraint_c, 0); + vec_add1 (constraints, constraint_tuple); + these_constraints++; + } these_constraints = this_reg->runs_after; - while (these_constraints && these_constraints [0]) - { - this_constraint_c = these_constraints[0]; + while (these_constraints && these_constraints[0]) + { + this_constraint_c = these_constraints[0]; - constraint_tuple = format (0, "%s,%s%c", - this_constraint_c, - node_name, 0); - vec_add1 (constraints, constraint_tuple); - these_constraints++; - } + constraint_tuple = format (0, "%s,%s%c", + this_constraint_c, node_name, 0); + vec_add1 (constraints, constraint_tuple); + these_constraints++; + } this_reg = this_reg->next; } @@ -136,52 +227,52 @@ ip_feature_init_cast (vlib_main_t * vm, this_constraint = constraints[i]; if (comma_split (this_constraint, &a_name, &b_name)) - return clib_error_return (0, "comma_split failed!"); - + return clib_error_return (0, "comma_split failed!"); + p = hash_get_mem (index_by_name, a_name); - /* + /* * Note: the next two errors mean that the xxx_FEATURE_INIT macros are * b0rked. As in: if you code "A depends on B," and you forget - * to define a FEATURE_INIT macro for B, you lose. + * to define a FEATURE_INIT macro for B, you lose. * Nonexistent graph nodes are tolerated. */ if (p == 0) - return clib_error_return (0, "feature node '%s' not found", a_name); + return clib_error_return (0, "feature node '%s' not found", a_name); a_index = p[0]; p = hash_get_mem (index_by_name, b_name); if (p == 0) - return clib_error_return (0, "feature node '%s' not found", b_name); + return clib_error_return (0, "feature node '%s' not found", b_name); b_index = p[0]; /* add a before b to the original set of constraints */ orig[a_index][b_index] = 1; vec_free (this_constraint); } - + /* Compute the positive transitive closure of the original constraints */ closure = clib_ptclosure (orig); /* Compute a partial order across feature nodes, if one exists. */ - again: +again: for (i = 0; i < n_features; i++) { for (j = 0; j < n_features; j++) - { - if (closure[i][j]) - goto item_constrained; - } + { + if (closure[i][j]) + goto item_constrained; + } /* Item i can be output */ vec_add1 (result, i); { - for (k = 0; k < n_features; k++) - closure [k][i] = 0; - /* - * Add a "Magic" a before a constraint. - * This means we'll never output it again - */ - closure [i][i] = 1; - goto again; + for (k = 0; k < n_features; k++) + closure[k][i] = 0; + /* + * Add a "Magic" a before a constraint. + * This means we'll never output it again + */ + closure[i][i] = 1; + goto again; } item_constrained: ; @@ -189,11 +280,11 @@ ip_feature_init_cast (vlib_main_t * vm, /* see if we got a partial order... */ if (vec_len (result) != n_features) - return clib_error_return - (0, "ip%s_feature_init_cast (cast=%d), no partial order!", - is_ip4 ? "4" : "6", cast); + return clib_error_return + (0, "ip%s_feature_init_cast (cast=%d), no partial order!", + is_ip4 ? "4" : "6", cast); - /* + /* * We win. * Bind the index variables, and output the feature node name vector * using the partial order we just computed. Result is in stack @@ -201,21 +292,20 @@ ip_feature_init_cast (vlib_main_t * vm, * is output first, etc. */ - for (i = n_features-1; i >= 0; i--) + for (i = n_features - 1; i >= 0; i--) { p = hash_get (reg_by_index, result[i]); ASSERT (p != 0); - this_reg = (vnet_ip_feature_registration_t *)p[0]; - *this_reg->feature_index = n_features - (i+1); + this_reg = (vnet_ip_feature_registration_t *) p[0]; + *this_reg->feature_index = n_features - (i + 1); vec_add1 (feature_nodes, this_reg->node_name); } - + /* Set up the config infrastructure */ vnet_config_init (vm, vcm, - feature_start_nodes, - num_feature_start_nodes, - feature_nodes, - vec_len(feature_nodes)); + feature_start_nodes, + num_feature_start_nodes, + feature_nodes, vec_len (feature_nodes)); /* Save a copy for show command */ if (is_ip4) @@ -224,12 +314,14 @@ ip_feature_init_cast (vlib_main_t * vm, im6->feature_nodes[cast] = feature_nodes; /* Finally, clean up all the shit we allocated */ + /* *INDENT-OFF* */ hash_foreach_pair (hp, index_by_name, ({ vec_add1 (keys_to_delete, (u8 *)hp->key); })); + /* *INDENT-ON* */ hash_free (index_by_name); - for (i = 0; i < vec_len(keys_to_delete); i++) + for (i = 0; i < vec_len (keys_to_delete); i++) vec_free (keys_to_delete[i]); vec_free (keys_to_delete); hash_free (reg_by_index); @@ -247,15 +339,19 @@ _(6, VNET_IP_RX_UNICAST_FEAT, "ip6 unicast") \ _(6, VNET_IP_RX_MULTICAST_FEAT, "ip6 multicast") \ _(6, VNET_IP_TX_FEAT, "ip6 output") +/** Display the set of available ip features. + Useful for verifying that expected features are present +*/ + static clib_error_t * show_ip_features_command_fn (vlib_main_t * vm, - unformat_input_t * input, - vlib_cli_command_t * cmd) + unformat_input_t * input, + vlib_cli_command_t * cmd) { - ip4_main_t * im4 = &ip4_main; - ip6_main_t * im6 = &ip6_main; + ip4_main_t *im4 = &ip4_main; + ip6_main_t *im6 = &ip6_main; int i; - char ** features; + char **features; vlib_cli_output (vm, "Available IP feature nodes"); @@ -272,88 +368,99 @@ show_ip_features_command_fn (vlib_main_t * vm, return 0; } +/* *INDENT-OFF* */ VLIB_CLI_COMMAND (show_ip_features_command, static) = { .path = "show ip features", .short_help = "show ip features", .function = show_ip_features_command_fn, }; +/* *INDENT-ON* */ + +/** Display the set of IP features configured on a specific interface + */ static clib_error_t * show_ip_interface_features_command_fn (vlib_main_t * vm, - unformat_input_t * input, - vlib_cli_command_t * cmd) + unformat_input_t * input, + vlib_cli_command_t * cmd) { - vnet_main_t * vnm = vnet_get_main(); - ip4_main_t * im4 = &ip4_main; - ip_lookup_main_t * lm4 = &im4->lookup_main; - ip6_main_t * im6 = &ip6_main; - ip_lookup_main_t * lm6 = &im6->lookup_main; - - ip_lookup_main_t * lm; - ip_config_main_t * cm; - vnet_config_main_t * vcm; - vnet_config_t * cfg; + vnet_main_t *vnm = vnet_get_main (); + ip4_main_t *im4 = &ip4_main; + ip_lookup_main_t *lm4 = &im4->lookup_main; + ip6_main_t *im6 = &ip6_main; + ip_lookup_main_t *lm6 = &im6->lookup_main; + + ip_lookup_main_t *lm; + ip_config_main_t *cm; + vnet_config_main_t *vcm; + vnet_config_t *cfg; u32 cfg_index; - vnet_config_feature_t * feat; - vlib_node_t * n; + vnet_config_feature_t *feat; + vlib_node_t *n; u32 sw_if_index; u32 node_index; u32 current_config_index; int i, af; u32 cast; - if (! unformat (input, "%U", unformat_vnet_sw_interface, - vnm, &sw_if_index)) + if (!unformat (input, "%U", unformat_vnet_sw_interface, vnm, &sw_if_index)) return clib_error_return (0, "Interface not specified..."); vlib_cli_output (vm, "IP feature paths configured on %U...", - format_vnet_sw_if_index_name, vnm, sw_if_index); + format_vnet_sw_if_index_name, vnm, sw_if_index); + - for (af = 0; af < 2; af++) { if (af == 0) - lm = lm4; + lm = lm4; else - lm = lm6; + lm = lm6; for (cast = VNET_IP_RX_UNICAST_FEAT; cast < VNET_N_IP_FEAT; cast++) - { - cm = lm->feature_config_mains + cast; - vcm = &cm->config_main; - - vlib_cli_output (vm, "\nipv%s %scast:", - (af == 0) ? "4" : "6", - cast == VNET_IP_RX_UNICAST_FEAT ? - "uni": "multi"); - - current_config_index = vec_elt (cm->config_index_by_sw_if_index, - sw_if_index); - - ASSERT(current_config_index - < vec_len (vcm->config_pool_index_by_user_index)); - - cfg_index = - vcm->config_pool_index_by_user_index[current_config_index]; - cfg = pool_elt_at_index (vcm->config_pool, cfg_index); - - for (i = 0; i < vec_len(cfg->features); i++) - { - feat = cfg->features + i; - node_index = feat->node_index; - n = vlib_get_node (vm, node_index); - vlib_cli_output (vm, " %v", n->name); - } - } + { + cm = lm->feature_config_mains + cast; + vcm = &cm->config_main; + + vlib_cli_output (vm, "\nipv%s %scast:", + (af == 0) ? "4" : "6", + cast == VNET_IP_RX_UNICAST_FEAT ? "uni" : "multi"); + + current_config_index = vec_elt (cm->config_index_by_sw_if_index, + sw_if_index); + + ASSERT (current_config_index + < vec_len (vcm->config_pool_index_by_user_index)); + + cfg_index = + vcm->config_pool_index_by_user_index[current_config_index]; + cfg = pool_elt_at_index (vcm->config_pool, cfg_index); + + for (i = 0; i < vec_len (cfg->features); i++) + { + feat = cfg->features + i; + node_index = feat->node_index; + n = vlib_get_node (vm, node_index); + vlib_cli_output (vm, " %v", n->name); + } + } } return 0; } +/* *INDENT-OFF* */ VLIB_CLI_COMMAND (show_ip_interface_features_command, static) = { .path = "show ip interface features", .short_help = "show ip interface features ", .function = show_ip_interface_features_command_fn, }; +/* *INDENT-ON* */ - +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ diff --git a/vnet/vnet/ip/ip_feature_registration.h b/vnet/vnet/ip/ip_feature_registration.h index 3c78abc0bc8..2d9a15bcf2c 100644 --- a/vnet/vnet/ip/ip_feature_registration.h +++ b/vnet/vnet/ip/ip_feature_registration.h @@ -16,23 +16,37 @@ #ifndef included_ip_feature_registration_h #define included_ip_feature_registration_h -typedef struct _vnet_ip_feature_registration { - struct _vnet_ip_feature_registration * next; - char * node_name; - u32 * feature_index; - char ** runs_before; - char ** runs_after; +/** feature registration object */ +typedef struct _vnet_ip_feature_registration +{ + /** next registration in list of all registrations*/ + struct _vnet_ip_feature_registration *next; + /** Graph node name */ + char *node_name; + /** Pointer to this feature index, filled in by ip_feature_init_cast */ + u32 *feature_index; + /** Constraints of the form "this feature runs before X" */ + char **runs_before; + /** Constraints of the form "this feature runs after Y" */ + char **runs_after; } vnet_ip_feature_registration_t; +/** Syntactic sugar, the c-compiler won't initialize registrations without it */ #define ORDER_CONSTRAINTS (char*[]) -clib_error_t * -ip_feature_init_cast (vlib_main_t * vm, - ip_config_main_t * cm, - vnet_config_main_t * vcm, - char **feature_start_nodes, - int num_feature_start_nodes, - vnet_cast_t cast, - int is_ip4); +clib_error_t *ip_feature_init_cast (vlib_main_t * vm, + ip_config_main_t * cm, + vnet_config_main_t * vcm, + char **feature_start_nodes, + int num_feature_start_nodes, + vnet_cast_t cast, int is_ip4); #endif /* included_ip_feature_registration_h */ + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ -- 2.16.6