Hello,
I would like to update the patch to
netkit-ftp-0.17/ftp/ftp.c,
a patch that serves to implement IPv6-capability for the ftp client binary.
This new text fixes two issues:
* Set the TCP port correctly for subsequent connection attempts.
The port number was inadvertedly not written in the first patch,
but was left as naught from the resolver's response.
* Shorten the TCP handshake timeout to ten seconds, using a SIGALRM
mechanism. This is desireable to quicken the precessing of those
addresses a name server might supply for a peer host, but which
in reality might be out of order. In particular, this is
desireable if IPv6 has not been configured on the peer host, thus
fooling connect() to wait for completion of the threeway handshake.
Regards,
--
Mats Erik Andersson, fil. dr
<mats.andersson@gisladisker.se>
Description: Impose IPv6-capacities on ftp.c.
Super structure 'struct sockaddr_storage' is replacing 'struct sockaddr_in'
.
For peer address strings, a first try aims at IPv4. That failing, next
try is for IPv6, and ultimatively a host lookup follows as last resort.
.
Use a SIGALRM mechanism to decrease the default TCP handshake timeout
to a value better suited for interactive use. The macro can be set
externally to change the suggested FTP_CONNECT_TIMEOUT=10
.
Use a command EPSV with explicit request for IPv6 address family as soon
as parsing concluded that the control socket is using IPv6.
Author: Mats Erik Andersson <debian@gisladisker.se>
Forwarded: no
Last-Updated: 2010-03-02
--- netkit-ftp-0.17/ftp/ftp.c.debian
+++ netkit-ftp-0.17/ftp/ftp.c
@@ -71,9 +71,11 @@
int data = -1;
off_t restart_point = 0;
-static struct sockaddr_in hisctladdr;
-static struct sockaddr_in data_addr;
-static struct sockaddr_in myctladdr;
+static char ipstring[INET6_ADDRSTRLEN]; /* Scribble area for resolver. */
+
+static struct sockaddr_storage hisctladdr;
+static struct sockaddr_storage data_addr;
+static struct sockaddr_storage myctladdr;
static int ptflag = 0;
static int ptabflg = 0;
@@ -95,10 +97,23 @@
static FILE *dataconn(const char *);
static void printbytes(off_t);
+#if ! defined(FTP_CONNECT_TIMEOUT) || FTP_CONNECT_TIMEOUT < 1
+# define FTP_CONNECT_TIMEOUT 10
+#endif
+
+static void
+trivial_alarm(int sig)
+{
+ /* Only used to generate an EINTR error. */
+ return;
+}
+
char *
hookup(char *host, int port)
{
- register struct hostent *hp = 0;
+ struct addrinfo hints, *ai = NULL, *aiptr = NULL;
+ struct sigaction sigact, oldsigact;
+ int status;
volatile int s = -1;
int tos;
socklen_t len;
@@ -106,29 +121,32 @@
sigjmp_buf jmploc;
sigjmp_buf *volatile oldtoplevel;
int dupfd;
+ struct sockaddr_in *hisctl_sa4 = (struct sockaddr_in *) &hisctladdr;
+ struct sockaddr_in6 *hisctl_sa6 = (struct sockaddr_in6 *) &hisctladdr;
memset(&hisctladdr, 0, sizeof(hisctladdr));
- if (inet_aton(host, &hisctladdr.sin_addr)) {
- hisctladdr.sin_family = AF_INET;
- strncpy(hostnamebuf, host, sizeof(hostnamebuf));
- hostnamebuf[sizeof(hostnamebuf)-1]=0;
- }
- else {
- hp = gethostbyname(host);
- if (hp == NULL) {
- fprintf(stderr, "ftp: %s: ", host);
- herror((char *)NULL);
- code = -1;
- return((char *) 0);
- }
- hisctladdr.sin_family = hp->h_addrtype;
- if (hp->h_length > (int)sizeof(hisctladdr.sin_addr)) {
- hp->h_length = sizeof(hisctladdr.sin_addr);
- }
- memcpy(&hisctladdr.sin_addr, hp->h_addr_list[0], hp->h_length);
- (void) strncpy(hostnamebuf, hp->h_name, sizeof(hostnamebuf));
- hostnamebuf[sizeof(hostnamebuf)-1] = 0;
+
+ sigact.sa_handler = trivial_alarm;
+ sigemptyset(&sigact.sa_mask);
+ sigact.sa_flags = 0;
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_flags = AI_ADDRCONFIG | AI_CANONNAME;
+ hints.ai_family = AF_UNSPEC;
+ hints.ai_socktype = SOCK_STREAM;
+
+ if ( (status = getaddrinfo(host, NULL, &hints, &ai)) ) {
+ fprintf(stderr, "ftp: %s: %s", host,
+ gai_strerror(status));
+ code = -1;
+ return((char *) 0);
}
+
+ aiptr = ai;
+ memcpy(&hisctladdr, aiptr->ai_addr, aiptr->ai_addrlen);
+ (void) strncpy(hostnamebuf, aiptr->ai_canonname,
+ sizeof(hostnamebuf));
+ hostnamebuf[sizeof(hostnamebuf)-1] = 0;
hostname = hostnamebuf;
oldtoplevel = toplevel;
@@ -141,32 +159,91 @@
toplevel = &jmploc;
INTOFF;
- s = socket(hisctladdr.sin_family, SOCK_STREAM, 0);
+ s = socket(hisctladdr.ss_family, SOCK_STREAM, 0);
INTON;
if (s < 0) {
perror("ftp: socket");
code = -1;
goto out;
}
- hisctladdr.sin_port = port;
- while (connect(s, (struct sockaddr *)&hisctladdr, sizeof (hisctladdr)) < 0) {
- if (hp && hp->h_addr_list[1]) {
+ switch (hisctladdr.ss_family) {
+ case AF_INET:
+ hisctl_sa4->sin_port = port;
+ break;
+ case AF_INET6:
+ hisctl_sa6->sin6_port = port;
+ }
+
+ sigaction(SIGALRM, &sigact, &oldsigact);
+ alarm(FTP_CONNECT_TIMEOUT);
+
+ while (connect(s, (struct sockaddr *)&hisctladdr,
+ (hisctladdr.ss_family == AF_INET)
+ ? sizeof(struct sockaddr_in)
+ : sizeof(struct sockaddr_in6))
+ < 0)
+ {
+ alarm(0);
+ sigaction(SIGALRM, &oldsigact, NULL);
+ if (errno == EINTR)
+ errno = ETIMEDOUT;
+
+ if (aiptr && aiptr->ai_next)
+ {
int oerrno = errno;
+ struct in_addr *ctladdr4 = &hisctl_sa4->sin_addr;
+ struct in6_addr *ctladdr6 = &hisctl_sa6->sin6_addr;
- fprintf(stderr, "ftp: connect to address %s: ",
- inet_ntoa(hisctladdr.sin_addr));
+ switch (aiptr->ai_family) {
+ case AF_INET:
+ fprintf(stderr, "ftp: connect to address %s: ",
+ inet_ntop(aiptr->ai_family,
+ ctladdr4,
+ ipstring,
+ sizeof(ipstring)));
+ break;
+ case AF_INET6:
+ fprintf(stderr, "ftp: connect to address %s: ",
+ inet_ntop(aiptr->ai_family,
+ ctladdr6,
+ ipstring,
+ sizeof(ipstring)));
+ }
errno = oerrno;
perror((char *) 0);
- hp->h_addr_list++;
- memcpy(&hisctladdr.sin_addr, hp->h_addr_list[0],
- hp->h_length);
- fprintf(stdout, "Trying %s...\n",
- inet_ntoa(hisctladdr.sin_addr));
+
+ aiptr = aiptr->ai_next;
+ memcpy(&hisctladdr, aiptr->ai_addr,
+ aiptr->ai_addrlen);
+ switch (hisctladdr.ss_family) {
+ case AF_INET:
+ hisctl_sa4->sin_port = port;
+ break;
+ case AF_INET6:
+ hisctl_sa6->sin6_port = port;
+ }
+
+ switch (aiptr->ai_family) {
+ case AF_INET:
+ fprintf(stdout, "Trying %s...\n",
+ inet_ntop(aiptr->ai_family,
+ ctladdr4,
+ ipstring,
+ sizeof(ipstring)));
+ break;
+ case AF_INET6:
+ fprintf(stdout, "Trying %s...\n",
+ inet_ntop(aiptr->ai_family,
+ ctladdr6,
+ ipstring,
+ sizeof(ipstring)));
+ }
INTOFF;
(void) close(s);
- s = socket(hisctladdr.sin_family, SOCK_STREAM, 0);
+ s = socket(aiptr->ai_family, SOCK_STREAM, 0);
INTON;
if (s < 0) {
+ freeaddrinfo(ai);
perror("ftp: socket");
code = -1;
goto out;
@@ -177,12 +254,17 @@
code = -1;
goto bad;
}
+ alarm(0);
+ sigaction(SIGALRM, &oldsigact, NULL);
+
len = sizeof (myctladdr);
if (getsockname(s, (struct sockaddr *)&myctladdr, &len) < 0) {
perror("ftp: getsockname");
code = -1;
goto bad;
}
+ if (ai)
+ freeaddrinfo(ai);
#ifdef IP_TOS
tos = IPTOS_LOWDELAY;
if (setsockopt(s, IPPROTO_IP, IP_TOS, (char *)&tos, sizeof(int)) < 0)
@@ -250,6 +332,8 @@
s = -1;
INTON;
out:
+ if (ai)
+ freeaddrinfo(ai);
toplevel = oldtoplevel;
return ((char *)0);
}
@@ -458,7 +542,7 @@
}
if (dig < 4 && isdigit(c))
code = code * 10 + (c - '0');
- if (!pflag && code == 227)
+ if (!pflag && (code == 227 || code == 229))
pflag = 1;
if (dig > 4 && pflag == 1 && isdigit(c))
pflag = 2;
@@ -1198,18 +1282,21 @@
static int
initconn(void)
{
- register char *p, *a;
+ register char *p = NULL, *a = NULL;
int result, tmpno = 0;
socklen_t len;
int on = 1;
int tos;
u_long a1,a2,a3,a4,p1,p2;
+ unsigned short int port;
+ struct sockaddr_in *data_addr_sa4 = (struct sockaddr_in *) &data_addr;
+ struct sockaddr_in6 *data_addr_sa6 = (struct sockaddr_in6 *) &data_addr;
if (passivemode) {
INTOFF;
if (data >= 0)
close(data);
- data = socket(AF_INET, SOCK_STREAM, 0);
+ data = socket(hisctladdr.ss_family, SOCK_STREAM, 0);
INTON;
if (data < 0) {
perror("ftp: socket");
@@ -1219,32 +1306,67 @@
setsockopt(data, SOL_SOCKET, SO_DEBUG, (char *)&on,
sizeof (on)) < 0)
perror("ftp: setsockopt (ignored)");
- if (command("PASV") != COMPLETE) {
- printf("Passive mode refused.\n");
- return(1);
- }
-
- /*
- * What we've got at this point is a string of comma separated
- * one-byte unsigned integer values, separated by commas.
- * The first four are the an IP address. The fifth is the MSB
- * of the port number, the sixth is the LSB. From that we'll
- * prepare a sockaddr_in.
- */
-
- if (sscanf(pasv,"%ld,%ld,%ld,%ld,%ld,%ld",
- &a1,&a2,&a3,&a4,&p1,&p2)
- != 6)
- {
- printf("Passive mode address scan failure. Shouldn't happen!\n");
- return(1);
+ switch (hisctladdr.ss_family) {
+ case AF_INET:
+ if (command("PASV") != COMPLETE) {
+ printf("Passive mode refused.\n");
+ return(1);
+ }
+ break;
+ case AF_INET6:
+ if (command("EPSV 2") != COMPLETE) {
+ printf("Passive mode refused.\n");
+ return(1);
+ }
}
- data_addr.sin_family = AF_INET;
- data_addr.sin_addr.s_addr = htonl((a1 << 24) | (a2 << 16) |
- (a3 << 8) | a4);
- data_addr.sin_port = htons((p1 << 8) | p2);
-
+ if (hisctladdr.ss_family == AF_INET) {
+ /*
+ * IPv4
+ *
+ * What we've got at this point is a string of
+ * comma separated one-byte unsigned integer
+ * values, separated by commas. The first four
+ * are the an IP address. The fifth is the MSB
+ * of the port number, the sixth is the LSB.
+ * From that we will prepare a sockaddr_in.
+ */
+
+ if (sscanf(pasv,"%ld,%ld,%ld,%ld,%ld,%ld",
+ &a1,&a2,&a3,&a4,&p1,&p2)
+ != 6)
+ {
+ printf("Passive mode address scan failure."
+ "Shouldn't happen!\n");
+ return(1);
+ }
+
+ data_addr.ss_family = AF_INET;
+ data_addr_sa4->sin_addr.s_addr =
+ htonl((a1 << 24) | (a2 << 16) |
+ (a3 << 8) | a4);
+ data_addr_sa4->sin_port = htons((p1 << 8) | p2);
+ } /* Old IPv4 command PASV */
+ else {
+ /* EPSV for IPv6
+ *
+ * Expected: pasv =~ "%u|"
+ *
+ * This is a shortcut based on the old code
+ * for getreply(), only altered to accept
+ * return code "229" for ESPV, in addition
+ * to "227" which goes with PASV.
+ */
+ if (sscanf(pasv, "%hu", &port) != 1) {
+ printf("Extended passive mode address "
+ "scan failure. Unfortunate!\n");
+ return(1);
+ }
+ data_addr = hisctladdr;
+ data_addr.ss_family = AF_INET6;
+ data_addr_sa6->sin6_port = htons(port);
+ } /* EPSV for IPv6 */
+
if (connect(data, (struct sockaddr *) &data_addr,
sizeof(data_addr))<0) {
perror("ftp: connect");
@@ -1261,11 +1383,18 @@
noport:
data_addr = myctladdr;
if (sendport)
- data_addr.sin_port = 0; /* let system pick one */
+ /* let the system pick a port */
+ switch (data_addr.ss_family) {
+ case AF_INET:
+ data_addr_sa4->sin_port = 0;
+ break;
+ case AF_INET6:
+ data_addr_sa6->sin6_port = 0;
+ }
INTOFF;
if (data != -1)
(void) close(data);
- data = socket(AF_INET, SOCK_STREAM, 0);
+ data = socket(data_addr.ss_family, SOCK_STREAM, 0);
INTON;
if (data < 0) {
perror("ftp: socket");
@@ -1293,13 +1422,23 @@
if (listen(data, 1) < 0)
perror("ftp: listen");
if (sendport) {
- a = (char *)&data_addr.sin_addr;
- p = (char *)&data_addr.sin_port;
#define UC(b) (((int)b)&0xff)
- result =
- command("PORT %d,%d,%d,%d,%d,%d",
- UC(a[0]), UC(a[1]), UC(a[2]), UC(a[3]),
- UC(p[0]), UC(p[1]));
+ switch (data_addr.ss_family) {
+ case AF_INET:
+ a = (char *)&data_addr_sa4->sin_addr;
+ p = (char *)&data_addr_sa4->sin_port;
+ result = command("PORT %d,%d,%d,%d,%d,%d",
+ UC(a[0]), UC(a[1]), UC(a[2]),
+ UC(a[3]), UC(p[0]), UC(p[1]));
+ break;
+ case AF_INET6:
+ result = command("EPRT |2|%s|%d|",
+ inet_ntop(data_addr.ss_family,
+ &data_addr_sa6->sin6_addr,
+ ipstring,
+ sizeof(ipstring)),
+ ntohs(data_addr_sa6->sin6_port));
+ }
if (result == ERROR && sendport == -1) {
sendport = 0;
tmpno = 1;
@@ -1327,7 +1466,7 @@
static FILE *
dataconn(const char *lmode)
{
- struct sockaddr_in from;
+ struct sockaddr_storage from;
int s, tos;
socklen_t fromlen = sizeof(from);
@@ -1398,8 +1537,8 @@
static struct comvars {
int connect;
char name[MAXHOSTNAMELEN];
- struct sockaddr_in mctl;
- struct sockaddr_in hctl;
+ struct sockaddr_storage mctl;
+ struct sockaddr_storage hctl;
FILE *in;
FILE *out;
int tpe;
Attachment:
signature.asc
Description: Digital signature