Split handshake() function into smaller functions

This commit is contained in:
Erik Ekman 2009-02-15 20:07:30 +00:00
parent f741e3d551
commit 7de1455c96
1 changed files with 161 additions and 79 deletions

View File

@ -498,22 +498,17 @@ send_codec_switch(int fd, int userid, int bits)
strncat(buf, topdomain, 512 - strlen(buf));
send_query(fd, buf);
}
static int
handshake(int dns_fd)
handshake_version(int dns_fd, int *seed)
{
struct timeval tv;
uint32_t payload;
char server[65];
char client[65];
char login[16];
char in[4096];
fd_set fds;
int read;
int mtu;
int seed;
uint32_t payload;
int i;
int r;
int read;
for (i = 0; running && i < 5; i++) {
tv.tv_sec = i + 1;
@ -544,11 +539,11 @@ handshake(int dns_fd)
((in[7] & 0xff)));
if (strncmp("VACK", in, 4) == 0) {
seed = payload;
*seed = payload;
userid = in[8];
printf("Version ok, both using protocol v 0x%08x. You are user #%d\n", VERSION, userid);
goto perform_login;
return 0;
} else if (strncmp("VNAK", in, 4) == 0) {
warnx("You use protocol v 0x%08x, server uses v 0x%08x. Giving up",
VERSION, payload);
@ -563,10 +558,24 @@ handshake(int dns_fd)
printf("Retrying version check...\n");
}
errx(1, "couldn't connect to server");
/* NOTREACHED */
perform_login:
warnx("couldn't connect to server");
return 1;
}
static int
handshake_login(int dns_fd, int seed)
{
struct timeval tv;
char in[4096];
char login[16];
char server[65];
char client[65];
int mtu;
fd_set fds;
int i;
int r;
int read;
login_calculate(login, 16, password, seed);
for (i=0; running && i<5 ;i++) {
@ -600,7 +609,7 @@ perform_login:
client[64] = 0;
if (tun_setip(client, netmask) == 0 &&
tun_setmtu(mtu) == 0) {
goto perform_case_check;
return 0;
} else {
warnx("Received handshake with bad data");
}
@ -614,8 +623,18 @@ perform_login:
}
warnx("couldn't login to server");
return 1;
}
static void
handshake_case_check(int dns_fd)
{
struct timeval tv;
char in[4096];
fd_set fds;
int i;
int r;
int read;
perform_case_check:
case_preserved = 0;
for (i=0; running && i<5 ;i++) {
tv.tv_sec = i + 1;
@ -635,7 +654,7 @@ perform_case_check:
if (in[0] == 'z' || in[0] == 'Z') {
if (read < (27 * 2)) {
printf("Received short case check reply. Will use base32 encoder\n");
goto switch_codec;
return;
} else {
int k;
@ -647,14 +666,14 @@ perform_case_check:
case_preserved = 0;
}
}
goto switch_codec;
return;
}
} else {
printf("Received bad case check reply\n");
}
} else {
printf("Got error on case check, will use base32\n");
goto switch_codec;
return;
}
}
@ -662,9 +681,17 @@ perform_case_check:
}
printf("No reply on case check, continuing\n");
switch_codec:
if (!case_preserved)
goto autodetect_max_fragsize;
}
static void
handshake_switch_codec(int dns_fd)
{
struct timeval tv;
char in[4096];
fd_set fds;
int i;
int r;
int read;
dataenc = get_base64_encoder();
printf("Switching to %s codec\n", dataenc->name);
@ -699,76 +726,99 @@ switch_codec:
}
in[read] = 0; /* zero terminate */
printf("Server switched to codec %s\n", in);
goto autodetect_max_fragsize;
return;
}
}
printf("Retrying codec switch...\n");
}
printf("No reply from server on codec switch. ");
codec_revert:
printf("Falling back to base32\n");
dataenc = get_base32_encoder();
autodetect_max_fragsize:
if (autodetect_frag_size) {
int proposed_fragsize = 768;
int range = 768;
max_downstream_frag_size = 0;
printf("Autoprobing max downstream fragment size... (skip with -m fragsize)\n");
while (running && range > 0 && (range >= 8 || !max_downstream_frag_size)) {
for (i=0; running && i<3 ;i++) {
tv.tv_sec = 1;
tv.tv_usec = 0;
send_fragsize_probe(dns_fd, proposed_fragsize);
}
FD_ZERO(&fds);
FD_SET(dns_fd, &fds);
static int
handshake_autoprobe_fragsize(int dns_fd)
{
struct timeval tv;
char in[4096];
fd_set fds;
int i;
int r;
int read;
int proposed_fragsize = 768;
int range = 768;
r = select(dns_fd + 1, &fds, NULL, NULL, &tv);
max_downstream_frag_size = 0;
printf("Autoprobing max downstream fragment size... (skip with -m fragsize)\n");
while (running && range > 0 && (range >= 8 || !max_downstream_frag_size)) {
for (i=0; running && i<3 ;i++) {
tv.tv_sec = 1;
tv.tv_usec = 0;
send_fragsize_probe(dns_fd, proposed_fragsize);
if(r > 0) {
read = read_dns(dns_fd, in, sizeof(in));
if (read > 0) {
/* We got a reply */
int acked_fragsize = ((in[0] & 0xff) << 8) | (in[1] & 0xff);
if (acked_fragsize == proposed_fragsize) {
if (read == proposed_fragsize) {
printf("%d ok.. ", acked_fragsize);
fflush(stdout);
max_downstream_frag_size = acked_fragsize;
range >>= 1;
proposed_fragsize += range;
continue;
} else {
goto badlen;
}
}
if (strncmp("BADIP", in, 5) == 0) {
printf("got BADIP.. ");
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) {
/* We got a reply */
int acked_fragsize = ((in[0] & 0xff) << 8) | (in[1] & 0xff);
if (acked_fragsize == proposed_fragsize) {
if (read == proposed_fragsize) {
printf("%d ok.. ", acked_fragsize);
fflush(stdout);
max_downstream_frag_size = acked_fragsize;
range >>= 1;
proposed_fragsize += range;
continue;
} else {
goto badlen;
}
}
if (strncmp("BADIP", in, 5) == 0) {
printf("got BADIP.. ");
fflush(stdout);
}
}
}
}
badlen:
printf("%d not ok.. ", proposed_fragsize);
fflush(stdout);
range >>= 1;
proposed_fragsize -= range;
}
if (!running) {
printf("\n");
warnx("stopped while autodetecting fragment size (Try probing manually with -m)");
return 1;
}
if (range == 0) {
/* Tried all the way down to 2 and found no good size */
printf("\n");
warnx("found no accepted fragment size. (Try probing manually with -m)");
return 1;
}
printf("will use %d\n", max_downstream_frag_size);
printf("%d not ok.. ", proposed_fragsize);
fflush(stdout);
range >>= 1;
proposed_fragsize -= range;
}
if (!running) {
printf("\n");
warnx("stopped while autodetecting fragment size (Try probing manually with -m)");
return 1;
}
if (range == 0) {
/* Tried all the way down to 2 and found no good size */
printf("\n");
warnx("found no accepted fragment size. (Try probing manually with -m)");
return 1;
}
printf("will use %d\n", max_downstream_frag_size);
return 0;
}
static void
handshake_set_fragsize(int dns_fd)
{
struct timeval tv;
char in[4096];
fd_set fds;
int i;
int r;
int read;
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;
@ -789,20 +839,52 @@ badlen:
if (strncmp("BADFRAG", in, 7) == 0) {
printf("Server rejected fragsize. Keeping default.");
goto done;
return;
} else if (strncmp("BADIP", in, 5) == 0) {
printf("Server rejected sender IP address.\n");
goto done;
return;
}
accepted_fragsize = ((in[0] & 0xff) << 8) | (in[1] & 0xff);
goto done;
return;
}
}
printf("Retrying set fragsize...\n");
}
printf("No reply from server when setting fragsize. Keeping default.\n");
done:
}
static int
handshake(int dns_fd)
{
int seed;
int r;
r = handshake_version(dns_fd, &seed);
if (r) {
return r;
}
r = handshake_login(dns_fd, seed);
if (r) {
return r;
}
handshake_case_check(dns_fd);
if (case_preserved) {
handshake_switch_codec(dns_fd);
}
if (autodetect_frag_size) {
r = handshake_autoprobe_fragsize(dns_fd);
if (r) {
return r;
}
}
handshake_set_fragsize(dns_fd);
return 0;
}