diff options
| -rw-r--r-- | configure.in | 15 | ||||
| -rw-r--r-- | doc/bird.sgml | 37 | ||||
| -rw-r--r-- | proto/bgp/attrs.c | 12 | ||||
| -rw-r--r-- | proto/bgp/bgp.h | 1 | ||||
| -rw-r--r-- | proto/bgp/config.Y | 3 | ||||
| -rw-r--r-- | sysdep/unix/main.c | 67 | ||||
| -rw-r--r-- | tools/Makefile.in | 1 |
7 files changed, 121 insertions, 15 deletions
diff --git a/configure.in b/configure.in index 230b57b4..46a6ecd9 100644 --- a/configure.in +++ b/configure.in @@ -13,6 +13,7 @@ AC_ARG_ENABLE(ipv6,[ --enable-ipv6 enable building of IPv6 version (d AC_ARG_WITH(sysconfig,[ --with-sysconfig=FILE use specified BIRD system configuration file]) AC_ARG_WITH(protocols,[ --with-protocols=LIST include specified routing protocols (default: all)],,[with_protocols="all"]) AC_ARG_WITH(sysinclude,[ --with-sysinclude=PATH search for system includes on specified place]) +AC_ARG_WITH(iproutedir,[ --with-iproutedir=PATH path to iproute2 config files (default: /etc/iproute2)],[given_iproutedir="yes"]) AC_ARG_VAR([FLEX], [location of the Flex program]) AC_ARG_VAR([BISON], [location of the Bison program]) AC_ARG_VAR([M4], [location of the M4 program]) @@ -105,12 +106,14 @@ elif test -f sysconfig.h ; then else case "$ip:$host_os" in ipv4:linux*) BIRD_CHECK_LINUX_VERSION + default_iproutedir="/etc/iproute2" case $bird_cv_sys_linux_version in 1.*|2.0.*) sysdesc=linux-20 ;; *) sysdesc=linux-22 ;; esac ;; ipv6:linux*) BIRD_CHECK_LINUX_VERSION + default_iproutedir="/etc/iproute2" case $bird_cv_sys_linux_version in 1.*|2.0.*) AC_MSG_ERROR([This version of Linux doesn't support IPv6.]) ;; *) sysdesc=linux-v6 ;; @@ -154,6 +157,15 @@ sysdep_dirs="`sed <$sysdesc '/^Link: /!d;s/^Link: \(.*\)$/\1/' | tr '\012' ' '` AC_MSG_RESULT($sysdep_dirs) AC_SUBST(sysdep_dirs) +if test "$with_iproutedir" = no ; then with_iproutedir= ; fi + +if test -n "$given_iproutedir" +then iproutedir=$with_iproutedir +else iproutedir=$default_iproutedir +fi + +AC_SUBST(iproutedir) + AC_MSG_CHECKING([protocols]) protocols=`echo "$with_protocols" | sed 's/,/ /g'` if test "$protocols" = no ; then protocols= ; fi @@ -234,11 +246,14 @@ $srcdir/tools/mergedirs $srcdir $srcdir_rel $objdir $sysdep_dirs]], AC_CONFIG_FILES($makefiles) AC_OUTPUT +rm -f $objdir/sysdep/paths.h + cat >&AC_FD_MSG <<EOF BIRD was configured with the following options: Source directory: $srcdir Object directory: $objdir + Iproute2 directory: $iproutedir System configuration: $sysdesc Debugging: $enable_debug Routing protocols: $protocols diff --git a/doc/bird.sgml b/doc/bird.sgml index 86f4c507..31b2c03f 100644 --- a/doc/bird.sgml +++ b/doc/bird.sgml @@ -266,8 +266,10 @@ protocol rip { about configuring protocols in their own chapters. You can run more than one instance of most protocols (like RIP or BGP). By default, no instances are configured. - <tag>define <m/constant/ = (<m/expression/)|<m/number/|<m/IP address/</tag> Define a constant. You can use it later in every place - you could use a simple integer or an IP address. + <tag>define <m/constant/ = (<m/expression/)|<m/number/|<m/IP address/</tag> + Define a constant. You can use it later in every place you could use a simple integer or an IP address. + Besides, there are some predefined numeric constants based on /etc/iproute2/rt_* files. + A list of defined constants can be seen (together with other symbols) using 'show symbols' command. <tag>router id <m/IPv4 address/</tag> Set BIRD's router ID. It's a world-wide unique identification of your router, usually one of router's IPv4 addresses. Default: in IPv4 version, the lowest IP address of a non-loopback interface. In IPv6 version, this option is mandatory. @@ -1121,7 +1123,7 @@ for each neighbor using the following configuration parameters: BIRD does not implement obsoleted RFC 1863, but uses ad-hoc implementation, which behaves like plain EBGP but reduces modifications to advertised route attributes to be transparent (for example does not prepend its AS number to - AS PATH attribute and keep MED attribute). Default: disabled. + AS PATH attribute and keeps MED attribute). Default: disabled. <tag>enable route refresh <m/switch/</tag> When BGP speaker changes its import filter, it has to re-examine all routes @@ -1205,6 +1207,15 @@ for each neighbor using the following configuration parameters: <tag>path metric <m/switch/</tag> Enable comparison of path lengths when deciding which BGP route is the best one. Default: on. + <tag>med metric <m/switch/</tag> Enable comparison of MED + attributes (during best route selection) even between routes + received from different ASes. This may be useful if all MED + attributes contain some consistent metric, perhaps enforced in + import filters of AS boundary routers. If this option is + disabled, MED attributes are compared only if routes are + received from the same AS (which is the standard behavior). + Default: off. + <tag>igp metric <m/switch/</tag> Enable comparison of internal distances to boundary routers during best route selection. Default: on. @@ -1233,21 +1244,21 @@ with `<tt/O/') are optional. <descrip> <tag>bgppath <cf/bgp_path/</tag> Sequence of AS numbers describing the AS path - the packet will travel through when forwarded according to the particular route. In case of - internal BGP it doesn't contain the number of the local AS. + the packet will travel through when forwarded according to the particular route. + In case of internal BGP it doesn't contain the number of the local AS. <tag>int <cf/bgp_local_pref/ [I]</tag> Local preference value used for selection among multiple BGP routes (see the selection rules above). It's used as an additional metric which is propagated through the whole local AS. <tag>int <cf/bgp_med/ [O]</tag> The Multiple Exit Discriminator of the route - is an optional attribute which is used on on external (inter-AS) links to + is an optional attribute which is used on external (inter-AS) links to convey to an adjacent AS the optimal entry point into the local AS. - The received attribute may be also propagated over internal BGP links - (and this is default behavior). The attribute value is zeroed when a route - is exported from a routing table to a BGP instance to ensure that the attribute - received from a neighboring AS is not propagated to other neighboring ASes. - A new value might be set in the export filter of a BGP instance. + The received attribute is also propagated over internal BGP links. + The attribute value is zeroed when a route is exported to an external BGP + instance to ensure that the attribute received from a neighboring AS is + not propagated to other neighboring ASes. A new value might be set in + the export filter of an external BGP instance. See RFC 4451<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4451.txt"> for further discussion of BGP MED attribute. @@ -1281,11 +1292,11 @@ with `<tt/O/') are optional. its own routing policy, it also has a complete freedom about which community attributes it defines and what will their semantics be. - <tag>quad <cf/bgp_originator_id/ [O]</tag> This attribute is created by the + <tag>quad <cf/bgp_originator_id/ [I, O]</tag> This attribute is created by the route reflector when reflecting the route and contains the router ID of the originator of the route in the local AS. - <tag>clist <cf/bgp_cluster_list/ [O]</tag> This attribute contains a list + <tag>clist <cf/bgp_cluster_list/ [I, O]</tag> This attribute contains a list of cluster IDs of route reflectors. Each route reflector prepends its cluster ID when reflecting the route. </descrip> diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c index e1a3671a..95eee9aa 100644 --- a/proto/bgp/attrs.c +++ b/proto/bgp/attrs.c @@ -1118,7 +1118,17 @@ bgp_rte_better(rte *new, rte *old) return 0; /* RFC 4271 9.1.2.2. c) Compare MED's */ - if (bgp_get_neighbor(new) == bgp_get_neighbor(old)) + /* This is noncompliant. Proper RFC 4271 path selection cannot be + * interpreted as finding the best path in some ordering. + * Therefore, it cannot be implemented in BIRD without some ugly + * hacks. This is just an approximation, which in specific + * situations may lead to persistent routing loops, because it is + * nondeterministic - it depends on the order in which routes + * appeared. But it is also the same behavior as used by default in + * Cisco routers, so it is probably not a big issue. + */ + if (new_bgp->cf->med_metric || old_bgp->cf->med_metric || + (bgp_get_neighbor(new) == bgp_get_neighbor(old))) { x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h index b06f20a0..097faa6a 100644 --- a/proto/bgp/bgp.h +++ b/proto/bgp/bgp.h @@ -25,6 +25,7 @@ struct bgp_config { int missing_lladdr; /* What we will do when we don' know link-local addr, see MLL_* */ int gw_mode; /* How we compute route gateway from next_hop attr, see GW_* */ int compare_path_lengths; /* Use path lengths when selecting best route */ + int med_metric; /* Compare MULTI_EXIT_DISC even between routes from differen ASes */ int igp_metric; /* Use IGP metrics when selecting best route */ int prefer_older; /* Prefer older routes according to RFC 5004 */ u32 default_local_pref; /* Default value for LOCAL_PREF attribute */ diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y index e932a7f6..93f832aa 100644 --- a/proto/bgp/config.Y +++ b/proto/bgp/config.Y @@ -25,7 +25,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, ADVERTISE, IPV4, CAPABILITIES, LIMIT, PASSIVE, PREFER, OLDER, MISSING, LLADDR, DROP, IGNORE, ROUTE, REFRESH, INTERPRET, COMMUNITIES, BGP_ORIGINATOR_ID, BGP_CLUSTER_LIST, IGP, TABLE, - GATEWAY, DIRECT, RECURSIVE) + GATEWAY, DIRECT, RECURSIVE, MED) CF_GRAMMAR @@ -79,6 +79,7 @@ bgp_proto: | bgp_proto GATEWAY DIRECT ';' { BGP_CFG->gw_mode = GW_DIRECT; } | bgp_proto GATEWAY RECURSIVE ';' { BGP_CFG->gw_mode = GW_RECURSIVE; } | bgp_proto PATH METRIC bool ';' { BGP_CFG->compare_path_lengths = $4; } + | bgp_proto MED METRIC bool ';' { BGP_CFG->med_metric = $4; } | bgp_proto IGP METRIC bool ';' { BGP_CFG->igp_metric = $4; } | bgp_proto PREFER OLDER bool ';' { BGP_CFG->prefer_older = $4; } | bgp_proto DEFAULT BGP_MED expr ';' { BGP_CFG->default_med = $4; } diff --git a/sysdep/unix/main.c b/sysdep/unix/main.c index 732c9169..fd921ace 100644 --- a/sysdep/unix/main.c +++ b/sysdep/unix/main.c @@ -62,6 +62,66 @@ async_dump(void) * Reading the Configuration */ +#ifdef PATH_IPROUTE_DIR + +static inline void +add_num_const(char *name, int val) +{ + struct symbol *s = cf_find_symbol(name); + s->class = SYM_NUMBER; + s->def = NULL; + s->aux = val; +} + +/* the code of read_iproute_table() is based on + rtnl_tab_initialize() from iproute2 package */ +static void +read_iproute_table(char *file, char *prefix, int max) +{ + char buf[512], namebuf[512]; + char *name; + int val; + FILE *fp; + + strcpy(namebuf, prefix); + name = namebuf + strlen(prefix); + + fp = fopen(file, "r"); + if (!fp) + return; + + while (fgets(buf, sizeof(buf), fp)) + { + char *p = buf; + + while (*p == ' ' || *p == '\t') + p++; + + if (*p == '#' || *p == '\n' || *p == 0) + continue; + + if (sscanf(p, "0x%x %s\n", &val, name) != 2 && + sscanf(p, "0x%x %s #", &val, name) != 2 && + sscanf(p, "%d %s\n", &val, name) != 2 && + sscanf(p, "%d %s #", &val, name) != 2) + continue; + + if (val < 0 || val > max) + continue; + + for(p = name; *p; p++) + if ((*p < 'a' || *p > 'z') && (*p < '0' || *p > '9') && (*p != '_')) + *p = '_'; + + add_num_const(namebuf, val); + } + + fclose(fp); +} + +#endif // PATH_IPROUTE_DIR + + static int conf_fd; static char *config_name = PATH_CONFIG; @@ -78,6 +138,13 @@ void sysdep_preconfig(struct config *c) { init_list(&c->logfiles); + +#ifdef PATH_IPROUTE_DIR + // read_iproute_table(PATH_IPROUTE_DIR "/rt_protos", "ipp_", 256); + read_iproute_table(PATH_IPROUTE_DIR "/rt_realms", "ipr_", 256); + read_iproute_table(PATH_IPROUTE_DIR "/rt_scopes", "ips_", 256); + read_iproute_table(PATH_IPROUTE_DIR "/rt_tables", "ipt_", 256); +#endif } int diff --git a/tools/Makefile.in b/tools/Makefile.in index 99ae2251..556eba5f 100644 --- a/tools/Makefile.in +++ b/tools/Makefile.in @@ -50,6 +50,7 @@ sysdep/paths.h: echo >sysdep/paths.h "/* Generated by Makefile, don't edit manually! */" echo >>sysdep/paths.h "#define PATH_CONFIG_DIR \"$(sysconfdir)\"" echo >>sysdep/paths.h "#define PATH_CONTROL_SOCKET_DIR \"$(localstatedir)/run\"" + if test -n "@iproutedir@" ; then echo >>sysdep/paths.h "#define PATH_IPROUTE_DIR \"@iproutedir@\"" ; fi tags: cd $(srcdir) ; etags -lc `find $(static-dirs) $(addprefix $(objdir)/,$(dynamic-dirs)) $(client-dirs) -name *.[chY]` |