diff options
Diffstat (limited to 'bgpd/bgp_filter.c')
| -rw-r--r-- | bgpd/bgp_filter.c | 658 |
1 files changed, 658 insertions, 0 deletions
diff --git a/bgpd/bgp_filter.c b/bgpd/bgp_filter.c new file mode 100644 index 0000000000..b544c716f7 --- /dev/null +++ b/bgpd/bgp_filter.c @@ -0,0 +1,658 @@ +/* AS path filter list. + Copyright (C) 1999 Kunihiro Ishiguro + +This file is part of GNU Zebra. + +GNU Zebra is free software; you can redistribute it and/or modify it +under the terms of the GNU General Public License as published by the +Free Software Foundation; either version 2, or (at your option) any +later version. + +GNU Zebra is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Zebra; see the file COPYING. If not, write to the Free +Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA +02111-1307, USA. */ + +#include <zebra.h> + +#include "command.h" +#include "log.h" +#include "memory.h" +#include "buffer.h" + +#include "bgpd/bgpd.h" +#include "bgpd/bgp_aspath.h" +#include "bgpd/bgp_regex.h" +#include "bgpd/bgp_filter.h" + +/* List of AS filter list. */ +struct as_list_list +{ + struct as_list *head; + struct as_list *tail; +}; + +/* AS path filter master. */ +struct as_list_master +{ + /* List of access_list which name is number. */ + struct as_list_list num; + + /* List of access_list which name is string. */ + struct as_list_list str; + + /* Hook function which is executed when new access_list is added. */ + void (*add_hook) (); + + /* Hook function which is executed when access_list is deleted. */ + void (*delete_hook) (); +}; + +/* Element of AS path filter. */ +struct as_filter +{ + struct as_filter *next; + struct as_filter *prev; + + enum as_filter_type type; + + regex_t *reg; + char *reg_str; +}; + +enum as_list_type +{ + ACCESS_TYPE_STRING, + ACCESS_TYPE_NUMBER +}; + +/* AS path filter list. */ +struct as_list +{ + char *name; + + enum as_list_type type; + + struct as_list *next; + struct as_list *prev; + + struct as_filter *head; + struct as_filter *tail; +}; + +/* ip as-path access-list 10 permit AS1. */ + +static struct as_list_master as_list_master = +{ + {NULL, NULL}, + {NULL, NULL}, + NULL, + NULL +}; + +/* Allocate new AS filter. */ +struct as_filter * +as_filter_new () +{ + struct as_filter *new; + + new = XMALLOC (MTYPE_AS_FILTER, sizeof (struct as_filter)); + memset (new, 0, sizeof (struct as_filter)); + return new; +} + +/* Free allocated AS filter. */ +void +as_filter_free (struct as_filter *asfilter) +{ + if (asfilter->reg) + bgp_regex_free (asfilter->reg); + if (asfilter->reg_str) + XFREE (MTYPE_AS_FILTER_STR, asfilter->reg_str); + XFREE (MTYPE_AS_FILTER, asfilter); +} + +/* Make new AS filter. */ +struct as_filter * +as_filter_make (regex_t *reg, char *reg_str, enum as_filter_type type) +{ + struct as_filter *asfilter; + + asfilter = as_filter_new (); + asfilter->reg = reg; + asfilter->type = type; + asfilter->reg_str = XSTRDUP (MTYPE_AS_FILTER_STR, reg_str); + + return asfilter; +} + +struct as_filter * +as_filter_lookup (struct as_list *aslist, char *reg_str, + enum as_filter_type type) +{ + struct as_filter *asfilter; + + for (asfilter = aslist->head; asfilter; asfilter = asfilter->next) + if (strcmp (reg_str, asfilter->reg_str) == 0) + return asfilter; + return NULL; +} + +void +as_list_filter_add (struct as_list *aslist, struct as_filter *asfilter) +{ + asfilter->next = NULL; + asfilter->prev = aslist->tail; + + if (aslist->tail) + aslist->tail->next = asfilter; + else + aslist->head = asfilter; + aslist->tail = asfilter; +} + +/* Lookup as_list from list of as_list by name. */ +struct as_list * +as_list_lookup (char *name) +{ + struct as_list *aslist; + + if (name == NULL) + return NULL; + + for (aslist = as_list_master.num.head; aslist; aslist = aslist->next) + if (strcmp (aslist->name, name) == 0) + return aslist; + + for (aslist = as_list_master.str.head; aslist; aslist = aslist->next) + if (strcmp (aslist->name, name) == 0) + return aslist; + + return NULL; +} + +struct as_list * +as_list_new () +{ + struct as_list *new; + + new = XMALLOC (MTYPE_AS_LIST, sizeof (struct as_list)); + memset (new, 0, sizeof (struct as_list)); + return new; +} + +void +as_list_free (struct as_list *aslist) +{ + XFREE (MTYPE_AS_LIST, aslist); +} + +/* Insert new AS list to list of as_list. Each as_list is sorted by + the name. */ +struct as_list * +as_list_insert (char *name) +{ + int i; + long number; + struct as_list *aslist; + struct as_list *point; + struct as_list_list *list; + + /* Allocate new access_list and copy given name. */ + aslist = as_list_new (); + aslist->name = strdup (name); + + /* If name is made by all digit character. We treat it as + number. */ + for (number = 0, i = 0; i < strlen (name); i++) + { + if (isdigit ((int) name[i])) + number = (number * 10) + (name[i] - '0'); + else + break; + } + + /* In case of name is all digit character */ + if (i == strlen (name)) + { + aslist->type = ACCESS_TYPE_NUMBER; + + /* Set access_list to number list. */ + list = &as_list_master.num; + + for (point = list->head; point; point = point->next) + if (atol (point->name) >= number) + break; + } + else + { + aslist->type = ACCESS_TYPE_STRING; + + /* Set access_list to string list. */ + list = &as_list_master.str; + + /* Set point to insertion point. */ + for (point = list->head; point; point = point->next) + if (strcmp (point->name, name) >= 0) + break; + } + + /* In case of this is the first element of master. */ + if (list->head == NULL) + { + list->head = list->tail = aslist; + return aslist; + } + + /* In case of insertion is made at the tail of access_list. */ + if (point == NULL) + { + aslist->prev = list->tail; + list->tail->next = aslist; + list->tail = aslist; + return aslist; + } + + /* In case of insertion is made at the head of access_list. */ + if (point == list->head) + { + aslist->next = list->head; + list->head->prev = aslist; + list->head = aslist; + return aslist; + } + + /* Insertion is made at middle of the access_list. */ + aslist->next = point; + aslist->prev = point->prev; + + if (point->prev) + point->prev->next = aslist; + point->prev = aslist; + + return aslist; +} + +struct as_list * +as_list_get (char *name) +{ + struct as_list *aslist; + + aslist = as_list_lookup (name); + if (aslist == NULL) + { + aslist = as_list_insert (name); + + /* Run hook function. */ + if (as_list_master.add_hook) + (*as_list_master.add_hook) (); + } + + return aslist; +} + +static char * +filter_type_str (enum as_filter_type type) +{ + switch (type) + { + case AS_FILTER_PERMIT: + return "permit"; + break; + case AS_FILTER_DENY: + return "deny"; + break; + default: + return ""; + break; + } +} + +void +as_list_delete (struct as_list *aslist) +{ + struct as_list_list *list; + struct as_filter *filter, *next; + + for (filter = aslist->head; filter; filter = next) + { + next = filter->next; + as_filter_free (filter); + } + + if (aslist->type == ACCESS_TYPE_NUMBER) + list = &as_list_master.num; + else + list = &as_list_master.str; + + if (aslist->next) + aslist->next->prev = aslist->prev; + else + list->tail = aslist->prev; + + if (aslist->prev) + aslist->prev->next = aslist->next; + else + list->head = aslist->next; + + as_list_free (aslist); +} + +static int +as_list_empty (struct as_list *aslist) +{ + if (aslist->head == NULL && aslist->tail == NULL) + return 1; + else + return 0; +} + +void +as_list_filter_delete (struct as_list *aslist, struct as_filter *asfilter) +{ + if (asfilter->next) + asfilter->next->prev = asfilter->prev; + else + aslist->tail = asfilter->prev; + + if (asfilter->prev) + asfilter->prev->next = asfilter->next; + else + aslist->head = asfilter->next; + + as_filter_free (asfilter); + + /* If access_list becomes empty delete it from access_master. */ + if (as_list_empty (aslist)) + as_list_delete (aslist); + + /* Run hook function. */ + if (as_list_master.delete_hook) + (*as_list_master.delete_hook) (); +} + +static int +as_filter_match (struct as_filter *asfilter, struct aspath *aspath) +{ + if (bgp_regexec (asfilter->reg, aspath) != REG_NOMATCH) + return 1; + return 0; +} + +/* Apply AS path filter to AS. */ +enum as_filter_type +as_list_apply (struct as_list *aslist, void *object) +{ + struct as_filter *asfilter; + struct aspath *aspath; + + aspath = (struct aspath *) object; + + if (aslist == NULL) + return AS_FILTER_DENY; + + for (asfilter = aslist->head; asfilter; asfilter = asfilter->next) + { + if (as_filter_match (asfilter, aspath)) + return asfilter->type; + } + return AS_FILTER_DENY; +} + +/* Add hook function. */ +void +as_list_add_hook (void (*func) ()) +{ + as_list_master.add_hook = func; +} + +/* Delete hook function. */ +void +as_list_delete_hook (void (*func) ()) +{ + as_list_master.delete_hook = func; +} + +int +as_list_dup_check (struct as_list *aslist, struct as_filter *new) +{ + struct as_filter *asfilter; + + for (asfilter = aslist->head; asfilter; asfilter = asfilter->next) + { + if (asfilter->type == new->type + && strcmp (asfilter->reg_str, new->reg_str) == 0) + return 1; + } + return 0; +} + +DEFUN (ip_as_path, ip_as_path_cmd, + "ip as-path access-list WORD (deny|permit) .LINE", + IP_STR + "BGP autonomous system path filter\n" + "Specify an access list name\n" + "Regular expression access list name\n" + "Specify packets to reject\n" + "Specify packets to forward\n" + "A regular-expression to match the BGP AS paths\n") +{ + enum as_filter_type type; + struct as_filter *asfilter; + struct as_list *aslist; + regex_t *regex; + struct buffer *b; + int i; + char *regstr; + int first = 0; + + /* Check the filter type. */ + if (strncmp (argv[1], "p", 1) == 0) + type = AS_FILTER_PERMIT; + else if (strncmp (argv[1], "d", 1) == 0) + type = AS_FILTER_DENY; + else + { + vty_out (vty, "filter type must be [permit|deny]%s", VTY_NEWLINE); + return CMD_WARNING; + } + + /* Check AS path regex. */ + b = buffer_new (1024); + for (i = 2; i < argc; i++) + { + if (first) + buffer_putc (b, ' '); + else + first = 1; + + buffer_putstr (b, argv[i]); + } + buffer_putc (b, '\0'); + + regstr = buffer_getstr (b); + buffer_free (b); + + regex = bgp_regcomp (regstr); + if (!regex) + { + free (regstr); + vty_out (vty, "can't compile regexp %s%s", argv[0], + VTY_NEWLINE); + return CMD_WARNING; + } + + asfilter = as_filter_make (regex, regstr, type); + + free (regstr); + + /* Install new filter to the access_list. */ + aslist = as_list_get (argv[0]); + + /* Duplicate insertion check. */; + if (as_list_dup_check (aslist, asfilter)) + as_filter_free (asfilter); + else + as_list_filter_add (aslist, asfilter); + + return CMD_SUCCESS; +} + +DEFUN (no_ip_as_path, + no_ip_as_path_cmd, + "no ip as-path access-list WORD (deny|permit) .LINE", + NO_STR + IP_STR + "BGP autonomous system path filter\n" + "Specify an access list name\n" + "Regular expression access list name\n" + "Specify packets to reject\n" + "Specify packets to forward\n" + "A regular-expression to match the BGP AS paths\n") +{ + enum as_filter_type type; + struct as_filter *asfilter; + struct as_list *aslist; + struct buffer *b; + int i; + int first = 0; + char *regstr; + regex_t *regex; + + /* Lookup AS list from AS path list. */ + aslist = as_list_lookup (argv[0]); + if (aslist == NULL) + { + vty_out (vty, "ip as-path access-list %s doesn't exist%s", argv[0], + VTY_NEWLINE); + return CMD_WARNING; + } + + /* Check the filter type. */ + if (strncmp (argv[1], "p", 1) == 0) + type = AS_FILTER_PERMIT; + else if (strncmp (argv[1], "d", 1) == 0) + type = AS_FILTER_DENY; + else + { + vty_out (vty, "filter type must be [permit|deny]%s", VTY_NEWLINE); + return CMD_WARNING; + } + + /* Compile AS path. */ + b = buffer_new (1024); + for (i = 2; i < argc; i++) + { + if (first) + buffer_putc (b, ' '); + else + first = 1; + + buffer_putstr (b, argv[i]); + } + buffer_putc (b, '\0'); + + regstr = buffer_getstr (b); + buffer_free (b); + + regex = bgp_regcomp (regstr); + if (!regex) + { + free (regstr); + vty_out (vty, "can't compile regexp %s%s", argv[0], + VTY_NEWLINE); + return CMD_WARNING; + } + + /* Lookup asfilter. */ + asfilter = as_filter_lookup (aslist, regstr, type); + + free (regstr); + bgp_regex_free (regex); + + if (asfilter == NULL) + { + vty_out (vty, "%s", VTY_NEWLINE); + return CMD_WARNING; + } + + as_list_filter_delete (aslist, asfilter); + + return CMD_SUCCESS; +} + +DEFUN (no_ip_as_path_all, + no_ip_as_path_all_cmd, + "no ip as-path access-list WORD", + NO_STR + IP_STR + "BGP autonomous system path filter\n" + "Specify an access list name\n" + "Regular expression access list name\n") +{ + struct as_list *aslist; + + aslist = as_list_lookup (argv[0]); + if (aslist == NULL) + { + vty_out (vty, "ip as-path access-list %s doesn't exist%s", argv[0], + VTY_NEWLINE); + return CMD_WARNING; + } + + as_list_delete (aslist); + + return CMD_SUCCESS; +} + +int +config_write_as_list (struct vty *vty) +{ + struct as_list *aslist; + struct as_filter *asfilter; + int write = 0; + + for (aslist = as_list_master.num.head; aslist; aslist = aslist->next) + for (asfilter = aslist->head; asfilter; asfilter = asfilter->next) + { + vty_out (vty, "ip as-path access-list %s %s %s%s", + aslist->name, filter_type_str (asfilter->type), + asfilter->reg_str, + VTY_NEWLINE); + write++; + } + + for (aslist = as_list_master.str.head; aslist; aslist = aslist->next) + for (asfilter = aslist->head; asfilter; asfilter = asfilter->next) + { + vty_out (vty, "ip as-path access-list %s %s %s%s", + aslist->name, filter_type_str (asfilter->type), + asfilter->reg_str, + VTY_NEWLINE); + write++; + } + return write; +} + +struct cmd_node as_list_node = +{ + AS_LIST_NODE, + "", + 1 +}; + +/* Register functions. */ +void +bgp_filter_init () +{ + install_node (&as_list_node, config_write_as_list); + + install_element (CONFIG_NODE, &ip_as_path_cmd); + install_element (CONFIG_NODE, &no_ip_as_path_cmd); + install_element (CONFIG_NODE, &no_ip_as_path_all_cmd); +} |