diff options
| -rw-r--r-- | lib/Makefile.am | 2 | ||||
| -rw-r--r-- | lib/hook.c | 56 | ||||
| -rw-r--r-- | lib/hook.h | 187 | ||||
| -rw-r--r-- | lib/libfrr.c | 6 | ||||
| -rw-r--r-- | lib/libfrr.h | 2 | ||||
| -rw-r--r-- | zebra/rtread_getmsg.c | 4 |
6 files changed, 256 insertions, 1 deletions
diff --git a/lib/Makefile.am b/lib/Makefile.am index 5731440640..7709ce45eb 100644 --- a/lib/Makefile.am +++ b/lib/Makefile.am @@ -33,6 +33,7 @@ libfrr_la_SOURCES = \ strlcpy.c \ strlcat.c \ module.c \ + hook.c \ # end BUILT_SOURCES = route_types.h gitversion.h command_parse.h command_lex.h @@ -57,6 +58,7 @@ pkginclude_HEADERS = \ spf_backoff.h \ srcdest_table.h \ module.h \ + hook.h \ libfrr.h \ # end diff --git a/lib/hook.c b/lib/hook.c new file mode 100644 index 0000000000..04d803cd8d --- /dev/null +++ b/lib/hook.c @@ -0,0 +1,56 @@ +/* + * Copyright (c) 2016 David Lamparter, for NetDEF, Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ + +#include "memory.h" +#include "hook.h" + +DEFINE_MTYPE_STATIC(LIB, HOOK_ENTRY, "Hook entry") + +void _hook_register(struct hook *hook, void *funcptr, void *arg, bool has_arg, + struct frrmod_runtime *module, const char *funcname) +{ + struct hookent *he = XCALLOC(MTYPE_HOOK_ENTRY, sizeof(*he)); + he->hookfn = funcptr; + he->hookarg = arg; + he->has_arg = has_arg; + he->module = module; + he->fnname = funcname; + + he->next = hook->entries; + hook->entries = he; +} + +void _hook_unregister(struct hook *hook, void *funcptr, + void *arg, bool has_arg) +{ + struct hookent *he, **prev; + + for (prev = &hook->entries; (he = *prev) != NULL; prev = &he->next) + if (he->hookfn == funcptr && he->hookarg == arg + && he->has_arg == has_arg) + { + *prev = he->next; + XFREE(MTYPE_HOOK_ENTRY, he); + break; + } +} + diff --git a/lib/hook.h b/lib/hook.h new file mode 100644 index 0000000000..0cb7ab5c7d --- /dev/null +++ b/lib/hook.h @@ -0,0 +1,187 @@ +/* + * Copyright (c) 2016 David Lamparter, for NetDEF, Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ + +#ifndef _FRR_HOOK_H +#define _FRR_HOOK_H + +#include <stdbool.h> + +#include "module.h" +#include "memory.h" + +/* type-safe subscribable hook points + * + * where "type-safe" applies to the function pointers used for subscriptions + * + * overall usage: + * - to create a hook: + * + * mydaemon.h: + * #include "hook.h" + * DECLARE_HOOK (some_update_event, (struct eventinfo *info), (info)) + * + * mydaemon.c: + * DEFINE_HOOK (some_update_event, (struct eventinfo *info), (info)) + * ... + * hook_call (some_update_event, info) + * + * Note: the second and third macro args must be the hook function's + * parameter list, with the same names for each parameter. The second + * macro arg is with types (used for defining things), the third arg is + * just the names (used for passing along parameters). + * + * Do not use parameter names starting with "hook", these can collide with + * names used by the hook code itself. + * + * The return value is always "int" for now; hook_call will sum up the + * return values from each registered user. Default is 0. + * + * There are no pre-defined semantics for the value, in most cases it is + * ignored. For success/failure indication, 0 should be success, and + * handlers should make sure to only return 0 or 1 (not -1 or other values). + * + * + * - to use a hook / create a handler: + * + * #include "mydaemon.h" + * int event_handler (struct eventinfo *info) { ... } + * hook_register (some_update_event, event_handler); + * + * or, if you need an argument to be passed along (addonptr will be added + * as first argument when calling the handler): + * + * #include "mydaemon.h" + * int event_handler (void *addonptr, struct eventinfo *info) { ... } + * hook_register_arg (some_update_event, event_handler, addonptr); + * + * (addonptr isn't typesafe, but that should be manageable.) + */ + +/* TODO: + * - hook_unregister_all_module() + * - introspection / CLI / debug + * - testcases ;) + * + * For loadable modules, the idea is that hooks could be automatically + * unregistered when a module is unloaded. + * + * It's also possible to add a constructor (MTYPE style) to DEFINE_HOOK, + * which would make it possible for the CLI to show all hooks and all + * registered handlers. + */ + +struct hookent { + struct hookent *next; + void *hookfn; /* actually a function pointer */ + void *hookarg; + bool has_arg; + struct frrmod_runtime *module; + const char *fnname; +}; + +struct hook { + const char *name; + struct hookent *entries; +}; + +/* subscribe/add callback function to a hook + * + * always use hook_register(), which uses the static inline helper from + * DECLARE_HOOK in order to get type safety + */ +extern void _hook_register(struct hook *hook, void *funcptr, void *arg, + bool has_arg, struct frrmod_runtime *module, + const char *funcname); +#define hook_register(hookname, func) \ + _hook_register(&_hook_ ## hookname, \ + _hook_typecheck_ ## hookname (func), \ + NULL, false, THIS_MODULE, #func) +#define hook_register_arg(hookname, func, arg) \ + _hook_register(&_hook_ ## hookname, \ + _hook_typecheck_arg_ ## hookname (func), \ + arg, true, THIS_MODULE, #func) + +extern void _hook_unregister(struct hook *hook, void *funcptr, void *arg, + bool has_arg); +#define hook_unregister(hookname, func) \ + _hook_unregister(&_hook_ ## hookname, \ + _hook_typecheck_ ## hookname (func), NULL, false) +#define hook_unregister_arg(hookname, func, arg) \ + _hook_unregister(&_hook_ ## hookname, \ + _hook_typecheck_arg_ ## hookname (func), arg, true) + +/* invoke hooks + * this is private (static) to the file that has the DEFINE_HOOK statement + */ +#define hook_call(hookname, ...) \ + hook_call_ ## hookname (__VA_ARGS__) + +/* helpers to add the void * arg */ +#define HOOK_ADDDEF(...) (void *hookarg , ## __VA_ARGS__) +#define HOOK_ADDARG(...) (hookarg , ## __VA_ARGS__) + +/* use in header file - declares the hook and its arguments + * usage: DECLARE_HOOK(my_hook, (int arg1, struct foo *arg2), (arg1, arg2)) + * as above, "passlist" must use the same order and same names as "arglist" + * + * theoretically passlist is not neccessary, but let's keep things simple and + * use exact same args on DECLARE and DEFINE. + */ +#define DECLARE_HOOK(hookname, arglist, passlist) \ + extern struct hook _hook_ ## hookname; \ + __attribute__((unused)) \ + static void *_hook_typecheck_ ## hookname ( \ + int (*funcptr) arglist) { \ + return (void *)funcptr; } \ + __attribute__((unused)) \ + static void *_hook_typecheck_arg_ ## hookname ( \ + int (*funcptr) HOOK_ADDDEF arglist) { \ + return (void *)funcptr; } + +/* use in source file - contains hook-related definitions. + */ +#define DEFINE_HOOK(hookname, arglist, passlist) \ + struct hook _hook_ ## hookname = { \ + .name = #hookname, \ + .entries = NULL, \ + }; \ + static int hook_call_ ## hookname arglist { \ + int hooksum = 0; \ + struct hookent *he = _hook_ ## hookname .entries; \ + void *hookarg; \ + union { \ + void *voidptr; \ + int (*fptr) arglist; \ + int (*farg) HOOK_ADDDEF arglist; \ + } hookp; \ + for (; he; he = he->next) { \ + hookarg = he->hookarg; \ + hookp.voidptr = he->hookfn; \ + if (!he->has_arg) \ + hooksum += hookp.fptr passlist; \ + else \ + hooksum += hookp.farg HOOK_ADDARG passlist; \ + } \ + return hooksum; \ + } + +#endif /* _FRR_HOOK_H */ diff --git a/lib/libfrr.c b/lib/libfrr.c index 5c047040ae..64f8be2ca6 100644 --- a/lib/libfrr.c +++ b/lib/libfrr.c @@ -30,6 +30,8 @@ #include "log_int.h" #include "module.h" +DEFINE_HOOK(frr_late_init, (struct thread_master *tm), (tm)) + const char frr_sysconfdir[] = SYSCONFDIR; const char frr_vtydir[] = DAEMON_VTY_DIR; @@ -311,9 +313,9 @@ int frr_getopt(int argc, char * const argv[], int *longindex) return opt; } +static struct thread_master *master; struct thread_master *frr_init(void) { - struct thread_master *master; struct option_chain *oc; struct frrmod_runtime *module; char moderr[256]; @@ -354,6 +356,8 @@ struct thread_master *frr_init(void) void frr_config_fork(void) { + hook_call(frr_late_init, master); + if (di->instance) { snprintf(config_default, sizeof(config_default), "%s/%s-%d.conf", frr_sysconfdir, di->name, di->instance); diff --git a/lib/libfrr.h b/lib/libfrr.h index 71225fad38..a40fc34892 100644 --- a/lib/libfrr.h +++ b/lib/libfrr.h @@ -27,6 +27,7 @@ #include "log.h" #include "getopt.h" #include "module.h" +#include "hook.h" #define FRR_NO_PRIVSEP (1 << 0) #define FRR_NO_TCPVTY (1 << 1) @@ -95,6 +96,7 @@ extern void frr_help_exit(int status); extern struct thread_master *frr_init(void); +DECLARE_HOOK(frr_late_init, (struct thread_master *tm), (tm)) extern void frr_config_fork(void); extern void frr_vty_serv(void); diff --git a/zebra/rtread_getmsg.c b/zebra/rtread_getmsg.c index 1007d0ac18..4d491f3200 100644 --- a/zebra/rtread_getmsg.c +++ b/zebra/rtread_getmsg.c @@ -31,6 +31,10 @@ #include "zebra/rib.h" #include "zebra/zserv.h" +/* Thank you, Solaris, for polluting application symbol namespace. */ +#undef hook_register +#undef hook_unregister + #include <sys/stream.h> #include <sys/tihdr.h> |