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respondd: use C modules instead of Lua to provide data

This commit is contained in:
Matthias Schiffer 2016-02-02 06:36:39 +01:00
parent bdb56bba02
commit fd06c7d67d
7 changed files with 2346 additions and 122 deletions
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7
net/respondd/Makefile
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@ -13,7 +13,7 @@ include $(INCLUDE_DIR)/cmake.mk
define Package/respondd
SECTION:=net
CATEGORY:=Network
DEPENDS:=+liblua
DEPENDS:=+libjson-c
TITLE:=Responds to multicast queries with answers generated by Lua code
endef
@ -29,4 +29,9 @@ define Package/respondd/install
$(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/bin/respondd $(1)/usr/bin/
endef
define Build/InstallDev
$(INSTALL_DIR) $(1)/usr/include
$(INSTALL_DATA) $(PKG_BUILD_DIR)/respondd.h $(1)/usr/include/
endef
$(eval $(call BuildPackage,respondd))

37
net/respondd/README.md Normal file
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@ -0,0 +1,37 @@
respondd providers are C modules (shared objects). These modules should include
<json-c/json.h> and <respondd.h>, the latter of which provides the following definitions:
typedef struct json_object * (*respondd_provider)(void);
struct respondd_provider_info {
const char *request;
const respondd_provider provider;
};
extern const struct respondd_provider_info respondd_providers[];
The module must define the array `respondd_providers`, e.g. like this:
static struct json_object * respondd_provider_nodeinfo(void) {
...
}
static struct json_object * respondd_provider_statistics(void) {
...
}
const struct respondd_provider_info respondd_providers[] = {
{"nodeinfo", respondd_provider_nodeinfo},
{"statistics", respondd_provider_statistics},
{}
};
The array must be terminated with an empty entry. The provider for each
request type must return a [JSON-C] JSON object. This JSON object must have exactly 1
reference, and all other memory must be freed by the provider before returning.
The JSON objects returned by different provider modules for the same request type
are merged.
[JSON-C]: https://github.com/json-c/json-c/wiki

13
net/respondd/src/CMakeLists.txt
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@ -1,14 +1,19 @@
cmake_minimum_required(VERSION 2.6)
set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR})
project(respondd C)
find_package(Lua51 REQUIRED)
find_package(JSON_C REQUIRED)
set_property(DIRECTORY PROPERTY COMPILE_DEFINITIONS _GNU_SOURCE)
include_directories(${LUA_INCLUDE_DIR})
add_executable(respondd respondd.c)
set_property(TARGET respondd PROPERTY COMPILE_FLAGS "-Wall -std=c99")
target_link_libraries(respondd ${LUA_LIBRARIES} dl)
set_property(TARGET respondd PROPERTY COMPILE_FLAGS "-Wall -std=c99 -fno-strict-aliasing ${JSON_C_CFLAGS_OTHER}")
set_property(TARGET respondd PROPERTY LINK_FLAGS "${JSON_C_LDFLAGS_OTHER}")
set_property(TARGET respondd APPEND PROPERTY INCLUDE_DIRECTORIES ${JSON_C_INCLUDE_DIR})
target_link_libraries(respondd ${JSON_C_LIBRARIES} dl)
install(TARGETS respondd RUNTIME DESTINATION bin)
install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/respondd.h DESTINATION include)

20
net/respondd/src/FindJSON_C.cmake Normal file
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@ -0,0 +1,20 @@
# Defines the following variables:
# JSON_C_FOUND
# JSON_C_INCLUDE_DIR
# JSON_C_LIBRARIES
# JSON_C_CFLAGS_OTHER
# JSON_C_LDFLAGS_OTHER
find_package(PkgConfig REQUIRED QUIET)
pkg_check_modules(_JSON_C json-c)
find_path(JSON_C_INCLUDE_DIR NAMES json-c/json.h HINTS ${_JSON_C_INCLUDE_DIRS})
find_library(JSON_C_LIBRARIES NAMES json-c HINTS ${_JSON_C_LIBRARY_DIRS})
set(JSON_C_CFLAGS_OTHER "${_JSON_C_CFLAGS_OTHER}" CACHE STRING "Additional compiler flags for json-c")
set(JSON_C_LDFLAGS_OTHER "${_JSON_C_LDFLAGS_OTHER}" CACHE STRING "Additional linker flags for json-c")
find_package_handle_standard_args(JSON_C REQUIRED_VARS JSON_C_LIBRARIES JSON_C_INCLUDE_DIR)
mark_as_advanced(JSON_C_INCLUDE_DIR JSON_C_LIBRARIES JSON_C_CFLAGS_OTHER JSON_C_LDFLAGS_OTHER)

1865
net/respondd/src/miniz.c Normal file
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File diff suppressed because it is too large Load Diff

487
net/respondd/src/respondd.c
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@ -1,6 +1,6 @@
/*
Copyright (c) 2014-2015, Nils Schneider <nils@nilsschneider.net>
Copyright (c) 2015, Matthias Schiffer <mschiffer@universe-factory.net>
Copyright (c) 2015-2016, Matthias Schiffer <mschiffer@universe-factory.net>
All rights reserved.
Redistribution and use in source and binary forms, with or without
@ -24,10 +24,18 @@
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <lua.h>
#include <lauxlib.h>
#include <lualib.h>
#include "respondd.h"
#include "miniz.c"
#include <json-c/json.h>
#include <alloca.h>
#include <dirent.h>
#include <dlfcn.h>
#include <inttypes.h>
#include <search.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@ -41,150 +49,395 @@
#include <sys/socket.h>
struct provider_list {
struct provider_list *next;
char *name;
respondd_provider provider;
};
struct request_type {
struct provider_list *providers;
struct json_object *cache;
uint64_t cache_time;
int64_t cache_timeout;
};
static int64_t now;
static struct hsearch_data htab;
static struct json_object * merge_json(struct json_object *a, struct json_object *b);
static void usage() {
puts("Usage: respondd [-h] -g <group> -p <port> -i <if0> [-i <if1> ..]");
puts(" -g <ip6> multicast group, e.g. ff02::2:1001");
puts(" -p <int> port number to listen on");
puts(" -i <string> interface on which the group is joined");
puts(" -c <string> Lua command");
puts(" -h this help\n");
puts("Usage:");
puts(" respondd -h");
puts(" respondd [-p <port>] [-g <group> -i <if0> [-i <if1> ..]] [-d <dir>]");
puts(" -p <int> port number to listen on");
puts(" -g <ip6> multicast group, e.g. ff02::2:1001");
puts(" -i <string> interface on which the group is joined");
puts(" -d <string> data provider directory (default: current directory)");
puts(" -h this help\n");
}
static void join_mcast(const int sock, const struct in6_addr addr, const char *iface) {
struct ipv6_mreq mreq;
struct ipv6_mreq mreq;
mreq.ipv6mr_multiaddr = addr;
mreq.ipv6mr_interface = if_nametoindex(iface);
mreq.ipv6mr_multiaddr = addr;
mreq.ipv6mr_interface = if_nametoindex(iface);
if (mreq.ipv6mr_interface == 0)
goto error;
if (mreq.ipv6mr_interface == 0)
goto error;
if (setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq, sizeof(mreq)) == -1)
goto error;
if (setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq, sizeof(mreq)) == -1)
goto error;
return;
return;
error:
fprintf(stderr, "Could not join multicast group on %s: ", iface);
perror(NULL);
fprintf(stderr, "Could not join multicast group on %s: ", iface);
perror(NULL);
}
static void serve(lua_State *L, int sock) {
char buffer[256];
ssize_t read_bytes;
struct timespec tp;
lua_pushvalue(L, -1);
static void update_time(void) {
struct timespec tp;
clock_gettime(CLOCK_MONOTONIC, &tp);
struct sockaddr_in6 addr;
socklen_t addrlen = sizeof(addr);
read_bytes = recvfrom(sock, buffer, sizeof(buffer), 0, (struct sockaddr *)&addr, &addrlen);
if (read_bytes < 0) {
perror("recvfrom failed");
exit(EXIT_FAILURE);
}
clock_gettime(CLOCK_MONOTONIC, &tp);
lua_pushlstring(L, buffer, read_bytes);
lua_pushnumber(L, tp.tv_sec + 1.0e-9*tp.tv_nsec);
if (lua_pcall(L, 2, 1, 0)) {
fprintf(stderr, "%s\n", lua_tostring(L, -1));
}
else if (lua_isstring(L, -1)) {
size_t msg_length;
const char *msg = lua_tolstring(L, -1, &msg_length);
if (sendto(sock, msg, msg_length, 0, (struct sockaddr *)&addr, addrlen) < 0)
perror("sendto failed");
}
lua_pop(L, 1);
now = (int64_t)tp.tv_sec * 1000 + tp.tv_nsec / 1000000;
}
/**
* Merges two JSON objects
*
* On conflicts, object a will be preferred.
*
* Internally, this functions merges all entries from object a into object b,
* so merging a small object a with a big object b is faster than vice-versa.
*/
static struct json_object * merge_json(struct json_object *a, struct json_object *b) {
if (!json_object_is_type(a, json_type_object) || !json_object_is_type(b, json_type_object)) {
json_object_put(b);
return a;
}
json_object_object_foreach(a, key, val_a) {
struct json_object *val_b;
json_object_get(val_a);
if (!json_object_object_get_ex(b, key, &val_b)) {
json_object_object_add(b, key, val_a);
continue;
}
json_object_get(val_b);
json_object_object_add(b, key, merge_json(val_a, val_b));
}
json_object_put(a);
return b;
}
static const struct respondd_provider_info * get_providers(const char *filename) {
/*
Prefix the filename with "./" to open the module in the current directory
(dlopen looks in the standard library paths by default)
*/
char path[2 + strlen(filename) + 1];
snprintf(path, sizeof(path), "./%s", filename);
void *handle = dlopen(path, RTLD_NOW|RTLD_LOCAL);
if (!handle)
return NULL;
const struct respondd_provider_info *ret = dlsym(handle, "respondd_providers");
if (!ret) {
dlclose(handle);
return NULL;
}
return ret;
}
static void load_cache_time(struct request_type *r, const char *name) {
r->cache = NULL;
r->cache_time = 0;
r->cache_timeout = now;
char filename[strlen(name) + 7];
snprintf(filename, sizeof(filename), "%s.cache", name);
FILE *f = fopen(filename, "r");
if (!f)
return;
fscanf(f, "%"SCNu64, &r->cache_time);
fclose(f);
}
static void add_provider(const char *name, const struct respondd_provider_info *provider) {
ENTRY key = {
.key = (char *)provider->request,
.data = NULL,
};
ENTRY *entry;
if (!hsearch_r(key, FIND, &entry, &htab)) {
struct request_type *r = malloc(sizeof(*r));
r->providers = NULL;
load_cache_time(r, provider->request);
key.data = r;
if (!hsearch_r(key, ENTER, &entry, &htab)) {
perror("hsearch_r");
exit(EXIT_FAILURE);
}
}
struct request_type *r = entry->data;
struct provider_list *pentry = malloc(sizeof(*pentry));
pentry->name = strdup(name);
pentry->provider = provider->provider;
struct provider_list **pos;
for (pos = &r->providers; *pos; pos = &(*pos)->next) {
if (strcmp(pentry->name, (*pos)->name) < 0)
break;
}
pentry->next = *pos;
*pos = pentry;
}
static void load_providers(void) {
update_time();
/* Maximum number of request types, might be made configurable in the future */
if (!hcreate_r(32, &htab)) {
perror("hcreate_r");
exit(EXIT_FAILURE);
}
DIR *dir = opendir(".");
if (!dir) {
perror("opendir");
exit(EXIT_FAILURE);
}
struct dirent *ent;
while ((ent = readdir(dir)) != NULL) {
if (ent->d_name[0] == '.')
continue;
size_t len = strlen(ent->d_name);
if (len < 4)
continue;
if (strcmp(&ent->d_name[len-3], ".so"))
continue;
const struct respondd_provider_info *providers = get_providers(ent->d_name);
if (!providers)
continue;
for (; providers->request; providers++)
add_provider(ent->d_name, providers);
}
closedir(dir);
}
static struct json_object * eval_providers(struct provider_list *providers) {
struct json_object *ret = json_object_new_object();
for (; providers; providers = providers->next)
ret = merge_json(providers->provider(), ret);
return ret;
}
static struct json_object * single_request(char *type) {
ENTRY key = {
.key = type,
.data = NULL,
};
ENTRY *entry;
if (!hsearch_r(key, FIND, &entry, &htab))
return NULL;
struct request_type *r = entry->data;
if (r->cache_time && now < r->cache_timeout)
return json_object_get(r->cache);
struct json_object *ret = eval_providers(r->providers);
if (r->cache_time) {
if (r->cache)
json_object_put(r->cache);
r->cache = json_object_get(ret);
r->cache_timeout = now + r->cache_time;
}
return ret;
}
static struct json_object * multi_request(char *types) {
struct json_object *ret = json_object_new_object();
char *type, *saveptr;
for (type = strtok_r(types, " ", &saveptr); type; type = strtok_r(NULL, " ", &saveptr)) {
struct json_object *sub = single_request(type);
if (sub)
json_object_object_add(ret, type, sub);
}
return ret;
}
static struct json_object * handle_request(char *request, bool *compress) {
if (!*request)
return NULL;
update_time();
if (!strncmp(request, "GET ", 4)) {
*compress = true;
return multi_request(request+4);
}
else {
*compress = false;
return single_request(request);
}
}
static void serve(int sock) {
char input[256];
const char *output = NULL;
ssize_t input_bytes, output_bytes;
struct sockaddr_in6 addr;
socklen_t addrlen = sizeof(addr);
bool compress;
input_bytes = recvfrom(sock, input, sizeof(input)-1, 0, (struct sockaddr *)&addr, &addrlen);
if (input_bytes < 0) {
perror("recvfrom failed");
exit(EXIT_FAILURE);
}
input[input_bytes] = 0;
struct json_object *result = handle_request(input, &compress);
if (!result)
return;
const char *str = json_object_to_json_string_ext(result, JSON_C_TO_STRING_PLAIN);
if (compress) {
size_t str_bytes = strlen(str);
mz_ulong compressed_bytes = mz_compressBound(str_bytes);
unsigned char *compressed = alloca(compressed_bytes);
if (!mz_compress(compressed, &compressed_bytes, (const unsigned char *)str, str_bytes)) {
output = (const char*)compressed;
output_bytes = compressed_bytes;
}
}
else {
output = str;
output_bytes = strlen(str);
}
if (output) {
if (sendto(sock, output, output_bytes, 0, (struct sockaddr *)&addr, addrlen) < 0)
perror("sendto failed");
}
json_object_put(result);
}
int main(int argc, char **argv) {
int sock;
struct sockaddr_in6 server_addr = {};
struct in6_addr mgroup_addr;
const char *command = NULL;
int sock;
struct sockaddr_in6 server_addr = {};
struct in6_addr mgroup_addr;
sock = socket(PF_INET6, SOCK_DGRAM, 0);
sock = socket(PF_INET6, SOCK_DGRAM, 0);
if (sock < 0) {
perror("creating socket");
exit(EXIT_FAILURE);
}
if (sock < 0) {
perror("creating socket");
exit(EXIT_FAILURE);
}
server_addr.sin6_family = AF_INET6;
server_addr.sin6_addr = in6addr_any;
server_addr.sin6_family = AF_INET6;
server_addr.sin6_addr = in6addr_any;
opterr = 0;
opterr = 0;
int group_set = 0;
int group_set = 0;
int c;
while ((c = getopt(argc, argv, "p:g:i:c:h")) != -1) {
switch (c) {
case 'p':
server_addr.sin6_port = htons(atoi(optarg));
break;
int c;
while ((c = getopt(argc, argv, "p:g:i:d:h")) != -1) {
switch (c) {
case 'p':
server_addr.sin6_port = htons(atoi(optarg));
break;
case 'g':
if (!inet_pton(AF_INET6, optarg, &mgroup_addr)) {
perror("Invalid multicast group. This message will probably confuse you");
exit(EXIT_FAILURE);
}
case 'g':
if (!inet_pton(AF_INET6, optarg, &mgroup_addr)) {
perror("Invalid multicast group. This message will probably confuse you");
exit(EXIT_FAILURE);
}
group_set = 1;
break;
group_set = 1;
break;
case 'i':
if (!group_set) {
fprintf(stderr, "Multicast group must be given before interface.\n");
exit(EXIT_FAILURE);
}
join_mcast(sock, mgroup_addr, optarg);
break;
case 'i':
if (!group_set) {
fprintf(stderr, "Multicast group must be given before interface.\n");
exit(EXIT_FAILURE);
}
join_mcast(sock, mgroup_addr, optarg);
break;
case 'c':
command = optarg;
break;
case 'd':
if (chdir(optarg)) {
perror("Unable to change to given directory");
exit(EXIT_FAILURE);
}
break;
case 'h':
usage();
exit(EXIT_SUCCESS);
break;
case 'h':
usage();
exit(EXIT_SUCCESS);
break;
default:
fprintf(stderr, "Invalid parameter %c ignored.\n", c);
}
}
default:
fprintf(stderr, "Invalid parameter -%c ignored.\n", optopt);
}
}
if (!command) {
fprintf(stderr, "No command given.\n");
exit(EXIT_FAILURE);
}
if (bind(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
perror("bind failed");
exit(EXIT_FAILURE);
}
if (bind(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
perror("bind failed");
exit(EXIT_FAILURE);
}
load_providers();
lua_State *L = luaL_newstate();
luaL_openlibs(L);
while (true)
serve(sock);
if (luaL_loadstring(L, command)) {
perror("Unable to load Lua command");
exit(EXIT_FAILURE);
}
lua_call(L, 0, 1);
while (1)
serve(L, sock);
return EXIT_FAILURE;
return EXIT_FAILURE;
}

39
net/respondd/src/respondd.h Normal file
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@ -0,0 +1,39 @@
/*
Copyright (c) 2016, Matthias Schiffer <mschiffer@universe-factory.net>
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _RESPONDD_H_
#define _RESPONDD_H_
typedef struct json_object * (*respondd_provider)(void);
struct respondd_provider_info {
const char *request;
const respondd_provider provider;
};
extern const struct respondd_provider_info respondd_providers[];
#endif /* _RESPONDD_H_ */