Changeset 9ababc

Timestamp:

01/05/09 20:47:59 (4 years ago)

Author:

Erik Ekman <yarrick@…>

Branches:

master

Children:

2bccb3

Parents:

d4e077

git-author:

Erik Ekman <yarrick@…> (01/05/09 20:47:59)

git-committer:

Erik Ekman <erik@…> (02/04/12 20:33:59)

Message:

#7, set max fragsize with -m in the client

Files:

• doc/proto_00000403.txt (modified) (1 diff)
• src/iodine.c (modified) (12 diffs)
• src/iodined.c (modified) (1 diff)

doc/proto_00000403.txt

@@ -47 +47 @@
         BADCODEC if not accepted. Client must then revert to Base32
 
+Set downstream fragment size:
+Client sends:
+        First byte n or N
+        Rest encoded with base32:
+        1 byte userid
+        2 bytes new downstream fragment size
+        CMC
+Server sends:
+        2 bytes new downstream fragment size. After this all downstream
+        payloads will be max (fragsize + 2) bytes long.
+        BADFRAG if not accepted.
+
 Data:
 Upstream data header:

src/iodine.c

@@ -65 +65 @@
 static int down_ack_fragment;
 
-/* Current IP packet */
+static int max_downstream_frag_size;
+static int autodetect_frag_size;
+
+/* Current up/downstream IP packet */
 static struct packet outpkt;
 static struct packet inpkt;
@@ -405 +408 @@
 
         send_packet(fd, 'P', data, sizeof(data));
+}
+
+static void
+send_set_downstream_fragsize(int fd, int fragsize)
+{
+        char data[5];
+        
+        data[0] = userid;
+        data[1] = (fragsize & 0xff00) >> 8;
+        data[2] = (fragsize & 0x00ff);
+        data[3] = (rand_seed >> 8) & 0xff;
+        data[4] = (rand_seed >> 0) & 0xff;
+        
+        rand_seed++;
+
+        send_packet(fd, 'N', data, sizeof(data));
 }
 
@@ -613 +632 @@
 switch_codec:
         if (!case_preserved)
-                return 0;
+                goto set_downstream_fragment_size;
 
         dataenc = get_base64_encoder();
@@ -648 +667 @@
                                 in[read] = 0; /* zero terminate */
                                 printf("Server switched to codec %s\n", in);
-                                return 0;
+                                goto autodetect_max_fragsize;
                         }
                 }
@@ -657 +676 @@
         printf("Falling back to base32\n");
         dataenc = get_base32_encoder();
+autodetect_max_fragsize:
+        if (autodetect_frag_size) {
+                printf("Autoprobing max downstream fragment size...\n");
+                /* TODO */
+        }
+set_downstream_fragment_size:
+        printf("Setting downstream fragment size to max %d...\n", max_downstream_frag_size);
+        for (i=0; running && i<5 ;i++) {
+                tv.tv_sec = i + 1;
+                tv.tv_usec = 0;
+
+                send_set_downstream_fragsize(dns_fd, max_downstream_frag_size);
+                
+                FD_ZERO(&fds);
+                FD_SET(dns_fd, &fds);
+
+                r = select(dns_fd + 1, &fds, NULL, NULL, &tv);
+
+                if(r > 0) {
+                        read = read_dns(dns_fd, in, sizeof(in));
+                        
+                        if (read > 0) {
+                                int accepted_fragsize;
+
+                                if (strncmp("BADFRAG", in, 7) == 0) {
+                                        printf("Server rejected fragsize. Keeping default.");
+                                        goto done;
+                                } else if (strncmp("BADIP", in, 5) == 0) {
+                                        printf("Server rejected sender IP address.\n");
+                                        goto done;
+                                }
+
+                                accepted_fragsize = ((in[0] & 0xff) << 8) | (in[1] & 0xff);
+                                goto done;
+                        }
+                }
+                printf("Retrying set fragsize...\n");
+        }
+        printf("No reply from server when setting fragsize. Keeping default.\n");
+done:
         return 0;
 }
-                
+
 static char *
 get_resolvconf_addr()
@@ -706 +765 @@
 
         printf("Usage: %s [-v] [-h] [-f] [-u user] [-t chrootdir] [-d device] "
-                        "[nameserver] topdomain\n", __progname);
+                        "[-P password] [-m maxfragsize] [nameserver] topdomain\n", __progname);
         exit(2);
 }
@@ -716 +775 @@
         printf("iodine IP over DNS tunneling client\n");
         printf("Usage: %s [-v] [-h] [-f] [-u user] [-t chrootdir] [-d device] "
-                        "[-P password] [nameserver] topdomain\n", __progname);
+                        "[-P password] [-m maxfragsize] [nameserver] topdomain\n", __progname);
         printf("  -v to print version info and exit\n");
         printf("  -h to print this help and exit\n");
@@ -724 +783 @@
         printf("  -d device to set tunnel device name\n");
         printf("  -P password used for authentication (max 32 chars will be used)\n");
+        printf("  -m maxfragsize, to limit size of downstream packets\n");
         printf("nameserver is the IP number of the relaying nameserver, if absent /etc/resolv.conf is used\n");
         printf("topdomain is the FQDN that is delegated to the tunnel endpoint.\n");
@@ -765 +825 @@
         inpkt.len = 0;
 
+        autodetect_frag_size = 1;
+        max_downstream_frag_size = 3072;
+
         b32 = get_base32_encoder();
         dataenc = get_base32_encoder();
@@ -776 +839 @@
 #endif
 
-        while ((choice = getopt(argc, argv, "vfhu:t:d:P:")) != -1) {
+        while ((choice = getopt(argc, argv, "vfhu:t:d:P:m:")) != -1) {
                 switch(choice) {
                 case 'v':
@@ -805 +868 @@
                         memset(optarg, 0, strlen(optarg)); 
                         break;
+                case 'm':
+                        autodetect_frag_size = 0;
+                        max_downstream_frag_size = atoi(optarg);
+                        break;
                 default:
                         usage();
@@ -834 +901 @@
         }
 
+        if (max_downstream_frag_size < 1 || max_downstream_frag_size > 0xffff) {
+                warnx("Use a max frag size between 1 and 65535 bytes.\n");
+                usage();
+                /* NOTREACHED */
+        }
+
         set_nameserver(nameserv_addr);
 

src/iodined.c

@@ -378 +378 @@
                 }
                 return;
+        } else if(in[0] == 'N' || in[0] == 'n') {
+                int max_frag_size;
+
+                read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, b32);
+                /* Downstream fragsize packet */
+                userid = unpacked[0];
+                if (userid < 0 || userid >= USERS || ip_cmp(userid, q) != 0) {
+                        write_dns(dns_fd, q, "BADIP", 5);
+                        return; /* illegal id */
+                }
+                                
+                max_frag_size = ((unpacked[1] & 0xff) << 8) | (unpacked[2] & 0xff);
+                if (max_frag_size < 1) {        
+                        write_dns(dns_fd, q, "BADFRAG", 7);
+                } else {
+                        users[userid].fragsize = max_frag_size;
+                        write_dns(dns_fd, q, &unpacked[1], 2);
+                }
+                return;
         } else if(in[0] == 'P' || in[0] == 'p') {
                 int dn_seq;