X-Git-Url: https://git.decadent.org.uk/gitweb/?a=blobdiff_plain;f=lib%2Fsnmp.c;h=cab421281a14ff1414c535daa2e841435b51c6ee;hb=17cd5711411f45df26b33c51288780627b7377e2;hp=f688c55d9242a473a203cc4b39985b630ecb35de;hpb=09ed626f25fb3e7c57ad7a59e5261ea005aa498f;p=ap-utils.git

diff --git a/lib/snmp.c b/lib/snmp.c
index f688c55..cab4212 100644
--- a/lib/snmp.c
+++ b/lib/snmp.c
@@ -2,7 +2,7 @@
  *	snmp.c from Access Point SNMP Utils for Linux
  *	basic snmp packets assembly/disassembly and send/receive functions
  *
- * Copyright (c) 2002 Roman Festchook <roma at polesye dot net>
+ * Copyright (c) Roman Festchook <roma at polesye dot net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License Version 2 from
@@ -21,31 +21,63 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <signal.h>
-#include <setjmp.h>
+#include <sys/time.h>
 #include <sys/types.h>
 #include <netinet/in.h>
 #include <sys/socket.h>
 #include <arpa/inet.h>
 #include "ap-utils.h"
 
-#define RETRIES 5
-
-sigjmp_buf position;
-
 extern char *community;
 extern short ap_type;
-extern int sockfd;
 extern struct in_addr ap_ip;
-int retries;
-char *buf = NULL;
 
-static void alarm_handler()
+int sockfd = 0, snmp_quit_by_keypress = 0;
+
+void close_sockfd()
+{
+    if (sockfd)
+	close(sockfd);
+}
+
+int open_sockfd()
+{
+    struct sockaddr_in client;
+
+    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
+	return -1;
+
+    memset(&client, 0, sizeof client);
+    client.sin_family = AF_INET;
+    client.sin_port = INADDR_ANY;
+    client.sin_addr.s_addr = INADDR_ANY;
+
+    if (bind(sockfd, (struct sockaddr *) &client, SIZE) == -1)
+	return -1;
+
+    return 0;
+}
+
+int reopen_sockfd()
 {
-    retries--;
-    siglongjmp(position, 1);
+    close_sockfd();
+    return (open_sockfd());
 }
 
+/*
+unsigned int ber_decode_uint(unsigned char *bevp, int len)
+{
+    unsigned int out = 0;
+
+    while (len--) {
+	out = (out << 7) | (*bevp & (*bevp & 0x80 ? 0x7f : 0xff));
+	bevp++;
+    }
+
+    return out;
+}
+*/
+
 int ber(char *message, varbind * varbindlist, int num, int type)
 {
 
@@ -130,43 +162,75 @@ int ber(char *message, varbind * varbindlist, int num, int type)
 
 int snmp(varbind * varbindlist, int num, int type)
 {
-    unsigned char message[1024], *start;
+    static char buf[1024];
+    unsigned char *start;
     unsigned int num_reply;
-    int len;
+    int len = 0, tries = 5;
     struct sockaddr_in server;
+    struct timeval timeout;
+    fd_set rds;
 
     if (num == 0)
 	return 1;
 
+    /*
+     * Flush sockfd by reopening. This prevents various 'something received/
+     * available on sockfd prior snmp() call' desync problems.
+     */
+    if (reopen_sockfd() == -1)
+	return 0;
+
     memset(&server, 0, sizeof server);
     server.sin_family = AF_INET;
     server.sin_port = htons(161);
     server.sin_addr.s_addr = ap_ip.s_addr;
 
-    signal(SIGALRM, alarm_handler);
-    retries = RETRIES;
-    sigsetjmp(position, 1);
-    if (!retries) {
-	return 0;
-    }
+    while (tries--) {
+	len = ber(buf, varbindlist, num, type);
+	if (sendto(sockfd, buf, len, 0, (struct sockaddr *) &server, SIZE)
+	    == -1) {
+	    return 0;
+	}
 
-    alarm(1);
-    len = ber(message, varbindlist, num, type);
-    if (sendto(sockfd, message, len, 0, (struct sockaddr *) &server, SIZE)
-	== -1) {
-	alarm(0);
-	return 0;
-    }
-    if ((len = recv(sockfd, message, 1024, 0)) == -1) {
-	alarm(0);
-	return 0;
+	FD_ZERO(&rds);
+	FD_SET(sockfd, &rds);
+	timeout.tv_sec = 1;
+	timeout.tv_usec = 0;
+
+	if (select(sockfd + 1, &rds, NULL, NULL, &timeout) == -1)
+	    return 0;
+
+	if (FD_ISSET(sockfd, &rds)) {
+	    if ((len = recv(sockfd, buf, sizeof buf, 0)) <= 0)
+		return 0;
+	    else
+		break;
+	}
+
+	/* timeout => next try, as long as no key has been pressed */
+
+	/*
+	 * Allow for quick 'last resort' escape using q/Q. Note:
+	 * we may not use one select() for checking both fd 0 and sockfd, since
+	 * something may appear on sockfd later than key has been pressed =>
+	 * give gratuitous 1sec delay for response arrival to sockfd, and THEN
+	 * just poll for anything on fd 0.
+	 */
+	if (snmp_quit_by_keypress && type == GET) {
+	    FD_ZERO(&rds);
+	    FD_SET(0, &rds);
+	    timeout.tv_sec = 0;
+	    timeout.tv_usec = 0;
+	    if (select(1, &rds, NULL, NULL, &timeout) == -1)
+		return 0;
+
+	    if (FD_ISSET(0, &rds))
+		return 0;
+	}
     }
-    alarm(0);
 
-    if (buf)
-	free(buf);
-    buf = (char *) malloc(len);
-    memcpy(buf, message, len);
+    if (!tries)
+	return 0;
 
     start = buf;
     num_reply = 0;