pattern_match_aescape(): Cleanup feature record setup
[pachi.git] / network.c
blob6692b509b59ad8515d2f5d41a36e6cee03c13742
1 /* Utility functions to redirect stdin, stdout, stderr to sockets. */
3 #define DEBUG
4 #include <stdio.h>
5 #include <string.h>
6 #include <stdlib.h>
7 #include <stdbool.h>
8 #include <assert.h>
9 #include <unistd.h>
10 #include <errno.h>
11 #include <pthread.h>
12 #include <sys/types.h>
13 #include <sys/socket.h>
14 #include <netdb.h>
16 #include "debug.h"
17 #include "util.h"
19 #define STDIN 0
20 #define STDOUT 1
21 #define STDERR 2
23 #define BSIZE 4096
25 static inline void
26 die(char *msg)
28 perror(msg);
29 exit(42);
32 /* Create a socket, bind to it on the given port and listen.
33 * This function is restricted to server mode (port has
34 * no hostname). Returns the socket. */
35 int
36 port_listen(char *port, int max_connections)
38 int sock = socket(AF_INET, SOCK_STREAM, 0);
39 if (sock == -1)
40 die("socket");
42 struct sockaddr_in server_addr;
43 memset(&server_addr, 0, sizeof(server_addr));
44 server_addr.sin_family = AF_INET;
45 server_addr.sin_port = htons(atoi(port));
46 server_addr.sin_addr.s_addr = INADDR_ANY;
48 if (bind(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1)
49 die("bind");
50 if (listen(sock, max_connections) == -1)
51 die("listen");
52 return sock;
55 /* Returns true if in private address range: 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 */
56 static bool
57 is_private(struct in_addr *in)
59 return (ntohl(in->s_addr) & 0xff000000) >> 24 == 10
60 || (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16
61 || (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168;
64 /* Waits for a connection on the given socket, and returns the file descriptor.
65 * Updates the client address if it is not null.
66 * WARNING: the connection is not authenticated. As a weak security measure,
67 * the connections are limited to a private network. */
68 int
69 open_server_connection(int socket, struct in_addr *client)
71 assert(socket >= 0);
72 for (;;) {
73 struct sockaddr_in client_addr;
74 int sin_size = sizeof(struct sockaddr_in);
75 int fd = accept(socket, (struct sockaddr *)&client_addr, (socklen_t *)&sin_size);
76 if (fd == -1) {
77 die("accept");
79 if (is_private(&client_addr.sin_addr)) {
80 if (client)
81 *client = client_addr.sin_addr;
82 return fd;
84 close(fd);
88 /* Opens a new connection to the given port name, which must
89 * contain a host name. Returns the open file descriptor,
90 * or -1 if the open fails. */
91 static int
92 open_client_connection(char *port_name)
94 char hostname[BSIZE];
95 strncpy(hostname, port_name, sizeof(hostname));
96 char *port = strchr(hostname, ':');
97 assert(port);
98 *port++ = '\0';
100 struct hostent *host = gethostbyname(hostname);
101 if (!host)
102 return -1;
103 int sock = socket(AF_INET, SOCK_STREAM, 0);
104 if (sock == -1)
105 die("socket");
106 struct sockaddr_in sin;
107 memcpy(&sin.sin_addr.s_addr, host->h_addr, host->h_length);
108 sin.sin_family = AF_INET;
109 sin.sin_port = htons(atoi(port));
111 if (connect(sock, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
112 close(sock);
113 return -1;
115 return sock;
118 /* Allow connexion queue > 1 to avoid race conditions. */
119 #define MAX_CONNEXIONS 5
121 struct port_info {
122 int socket;
123 char *port;
126 /* Wait at most 30s between connection attempts. */
127 #define MAX_WAIT 30
129 /* Open a connection on the given socket/port.
130 * Act as server if the port doesn't contain a hostname,
131 * as a client otherwise. If socket < 0 or in client mode,
132 * create the socket from the given port and update socket.
133 * Block until the connection succeeds.
134 * Return a file descriptor for the new connection. */
135 static int
136 open_connection(struct port_info *info)
138 int conn;
139 char *p = strchr(info->port, ':');
140 if (p) {
141 for (int try = 1;; ) {
142 conn = open_client_connection(info->port);
143 if (conn >= 0) break;
144 sleep(try);
145 if (try < MAX_WAIT) try++;
147 info->socket = conn;
148 } else {
149 if (info->socket < 0)
150 info->socket = port_listen(info->port, MAX_CONNEXIONS);
151 conn = open_server_connection(info->socket, NULL);
153 return conn;
156 /* Open the log connection on the given port, redirect stderr to it. */
157 static void
158 open_log_connection(struct port_info *info)
160 int log_conn = open_connection(info);
161 if (dup2(log_conn, STDERR) < 0)
162 die("dup2");
163 if (DEBUGL(0))
164 fprintf(stderr, "log connection opened\n");
167 /* Thread keeping the log connection open and redirecting stderr to it.
168 * It also echoes its input, which can be used to check if the
169 * program is alive. As a weak identity check, in server mode the input
170 * must start with "Pachi" (without the quotes). */
171 static void *
172 log_thread(void *arg)
174 struct port_info *info = arg;
175 assert(info && info->port);
176 for (;;) {
177 char buf[BSIZE];
178 int size;
179 bool check = !strchr(info->port, ':');
180 if (!check)
181 write(STDERR, "Pachi\n", 6);
182 while ((size = read(STDERR, buf, BSIZE)) > 0) {
183 if (check && strncasecmp(buf, "Pachi", 5)) break;
184 check = false;
185 write(STDERR, buf, size);
187 fflush(stderr);
188 open_log_connection(info);
192 /* Open the log connection on the given port, redirect stderr to it,
193 * and keep reopening it if the connection is closed. */
194 void
195 open_log_port(char *port)
197 pthread_t thread;
198 static struct port_info log_info = { .socket = -1 };
199 log_info.port = port;
200 open_log_connection(&log_info);
202 /* From now on, log_info may only be modified by the single
203 * log_thread so static allocation is ok and there is no race. */
204 pthread_create(&thread, NULL, log_thread, (void *)&log_info);
207 /* Open the gtp connection on the given port, redirect stdin & stdout to it. */
208 void
209 open_gtp_connection(int *socket, char *port)
211 static struct port_info gtp_info = { .socket = -1 };
212 gtp_info.port = port;
213 int gtp_conn = open_connection(&gtp_info);
214 for (int d = STDIN; d <= STDOUT; d++) {
215 if (dup2(gtp_conn, d) < 0)
216 die("dup2");
218 if (DEBUGL(0))
219 fprintf(stderr, "gtp connection opened\n");