Add support for IPv6 in the server and client.

Add support for IPv6 in the server and client.
You can force the use of IPv4 or IPv6 only with new
-4 and -6 commandline options, if IPv6 support was compiled in.

Signed-off-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

9 files changed, 575 insertions, 186 deletions

diff --git a/common/tftpsubs.c b/common/tftpsubs.c
index ef05cc4..45f4907 100644
--- a/common/tftpsubs.c
+++ b/common/tftpsubs.c
@@ -237,7 +237,7 @@ int synchnet(int f)
 {                               /* socket to flush */
     int pktcount = 0;
     char rbuf[PKTSIZE];
-    struct sockaddr_in from;
+    union sock_addr from;
     socklen_t fromlen;
     fd_set socketset;
     struct timeval notime;
@@ -253,15 +253,15 @@ int synchnet(int f)
 
         /* Otherwise drain the packet */
         pktcount++;
-        fromlen = sizeof from;
+        fromlen = sizeof(from);
         (void)recvfrom(f, rbuf, sizeof(rbuf), 0,
-                       (struct sockaddr *)&from, &fromlen);
+                       &from.sa, &fromlen);
     }
 
     return pktcount;            /* Return packets drained */
 }
 
-int pick_port_bind(int sockfd, struct sockaddr_in *myaddr,
+int pick_port_bind(int sockfd, union sock_addr *myaddr,
                    unsigned int port_range_from,
                    unsigned int port_range_to)
 {
@@ -279,9 +279,8 @@ int pick_port_bind(int sockfd, struct sockaddr_in *myaddr,
     port = firstport;
 
     do {
-        myaddr->sin_port = htons(port);
-
-        if (bind(sockfd, (struct sockaddr *)myaddr, sizeof *myaddr) < 0) {
+        sa_set_port(myaddr, htons(port));
+        if (bind(sockfd, &myaddr->sa, SOCKLEN(myaddr)) < 0) {
             /* Some versions of Linux return EINVAL instead of EADDRINUSE */
             if (!(port_range && (errno == EINVAL || errno == EADDRINUSE)))
                 return -1;
@@ -299,3 +298,34 @@ int pick_port_bind(int sockfd, struct sockaddr_in *myaddr,
 
     return -1;
 }
+
+int
+set_sock_addr(char *host,union sock_addr  *s, char **name)
+{
+    struct addrinfo *addrResult;
+    struct addrinfo hints;
+    int err;
+
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = s->sa.sa_family;
+    hints.ai_flags = AI_CANONNAME;
+    err = getaddrinfo(host, NULL, &hints, &addrResult);
+    if (err) {
+        printf("Error : %s\n", gai_strerror(err));
+        printf("%s: unknown host\n", host);
+        return err;
+    }
+    if (addrResult == NULL) {
+        printf("%s: unknown host\n", host);
+        return EAI_NONAME;
+    }
+    memcpy(s, addrResult->ai_addr, addrResult->ai_addrlen);
+    if (name) {
+        if (addrResult->ai_canonname)
+            *name = xstrdup(addrResult->ai_canonname);
+        else
+            *name = xstrdup(host);
+    }
+    freeaddrinfo(addrResult);
+    return 0;
+}
diff --git a/common/tftpsubs.h b/common/tftpsubs.h
index a5c88e3..20cf47e 100644
--- a/common/tftpsubs.h
+++ b/common/tftpsubs.h
@@ -40,6 +40,58 @@
 
 #include "config.h"
 
+union sock_addr {
+    struct sockaddr     sa;
+    struct sockaddr_in  si;
+#ifdef HAVE_IPV6
+    struct sockaddr_in6 s6;
+#endif
+};
+
+#define SOCKLEN(sock) \
+    (((union sock_addr*)sock)->sa.sa_family == AF_INET ? \
+    (sizeof(struct sockaddr_in)) : \
+    (sizeof(union sock_addr)))
+
+#ifdef HAVE_IPV6
+#define SOCKPORT(sock) \
+    (((union sock_addr*)sock)->sa.sa_family == AF_INET ? \
+    ((union sock_addr*)sock)->si.sin_port : \
+    ((union sock_addr*)sock)->s6.sin6_port)
+#else
+#define SOCKPORT(sock) \
+    (((union sock_addr*)sock)->si.sin_port)
+#endif
+
+#ifdef HAVE_IPV6
+#define SOCKADDR_P(sock) \
+    (((union sock_addr*)sock)->sa.sa_family == AF_INET ? \
+    (void *)&((union sock_addr*)sock)->si.sin_addr : \
+    (void *)&((union sock_addr*)sock)->s6.sin6_addr)
+#else
+#define SOCKADDR_P(sock) \
+    (void *)&((union sock_addr*)sock)->si.sin_addr
+#endif
+
+static inline int sa_set_port(union sock_addr *s, u_short port)
+{
+       switch (s->sa.sa_family) {
+       case AF_INET:
+               s->si.sin_port = port;
+               break;
+#ifdef HAVE_IPV6
+       case AF_INET6:
+               s->s6.sin6_port = port;
+               break;
+#endif
+       default:
+               return -1;
+       }
+       return 0;
+}
+
+int set_sock_addr(char *, union sock_addr *, char **);
+
 struct tftphdr;
 
 struct tftphdr *r_init(void);
@@ -55,7 +107,7 @@ int writeit(FILE *, struct tftphdr **, int, int);
 extern int segsize;
 #define MAX_SEGSIZE	65464
 
-int pick_port_bind(int sockfd, struct sockaddr_in *myaddr,
+int pick_port_bind(int sockfd, union sock_addr *myaddr,
                    unsigned int from, unsigned int to);
 
 #endif
diff --git a/tftp/main.c b/tftp/main.c
index ec57bc2..6176b37 100644
--- a/tftp/main.c
+++ b/tftp/main.c
@@ -40,7 +40,6 @@
  */
 #include <sys/file.h>
 #include <ctype.h>
-#include <netdb.h>
 #ifdef WITH_READLINE
 #include <readline/readline.h>
 #ifdef HAVE_READLINE_HISTORY_H
@@ -72,8 +71,16 @@ static const struct modes modes[] = {
 #define MODE_NETASCII (&modes[0])
 #define MODE_DEFAULT  MODE_NETASCII
 
-struct sockaddr_in peeraddr;
-int f;
+#ifdef HAVE_IPV6
+int ai_fam = AF_UNSPEC;
+int ai_fam_sock = AF_UNSPEC;
+#else
+int ai_fam = AF_INET;
+int ai_fam_sock = AF_INET;
+#endif
+
+union sock_addr peeraddr;
+int f = -1;
 u_short port;
 int trace;
 int verbose;
@@ -184,14 +191,18 @@ const char *program;
 static inline void usage(int errcode)
 {
     fprintf(stderr,
+#ifdef HAVE_IPV6
+            "Usage: %s [-4][-6][-v][-l][-m mode] [host [port]] [-c command]\n",
+#else
             "Usage: %s [-v][-l][-m mode] [host [port]] [-c command]\n",
+#endif
             program);
     exit(errcode);
 }
 
 int main(int argc, char *argv[])
 {
-    struct sockaddr_in s_in;
+    union sock_addr sa;
     int arg;
     static int pargc, peerargc;
     static int iscmd = 0;
@@ -210,6 +221,14 @@ int main(int argc, char *argv[])
         if (argv[arg][0] == '-') {
             for (optx = &argv[arg][1]; *optx; optx++) {
                 switch (*optx) {
+#ifdef HAVE_IPV6
+                case '4':
+                    ai_fam = AF_INET;
+                    break;
+                case '6':
+                    ai_fam = AF_INET6;
+                    break;
+#endif
                 case 'v':
                     verbose = 1;
                     break;
@@ -268,6 +287,8 @@ int main(int argc, char *argv[])
         }
     }
 
+    ai_fam_sock = ai_fam;
+
     pargv = argv + arg;
     pargc = argc - arg;
 
@@ -283,18 +304,7 @@ int main(int argc, char *argv[])
         sp->s_port = htons(IPPORT_TFTP);
         sp->s_proto = (char *)"udp";
     }
-    port = sp->s_port;          /* Default port */
-    f = socket(AF_INET, SOCK_DGRAM, 0);
-    if (f < 0) {
-        perror("tftp: socket");
-        exit(EX_OSERR);
-    }
-    bzero((char *)&s_in, sizeof(s_in));
-    s_in.sin_family = AF_INET;
-    if (pick_port_bind(f, &s_in, portrange_from, portrange_to)) {
-        perror("tftp: bind");
-        exit(EX_OSERR);
-    }
+
     bsd_signal(SIGINT, intr);
 
     if (peerargc) {
@@ -304,6 +314,21 @@ int main(int argc, char *argv[])
         setpeer(peerargc, peerargv);
     }
 
+    if (ai_fam_sock == AF_UNSPEC)
+        ai_fam_sock = AF_INET;
+
+    f = socket(ai_fam_sock, SOCK_DGRAM, 0);
+    if (f < 0) {
+        perror("tftp: socket");
+        exit(EX_OSERR);
+    }
+    bzero(&sa, sizeof(sa));
+    sa.sa.sa_family = ai_fam_sock;
+    if (pick_port_bind(f, &sa, portrange_from, portrange_to)) {
+        perror("tftp: bind");
+        exit(EX_OSERR);
+    }
+
     if (iscmd && pargc) {
         /* -c specified; execute command and exit */
         struct cmd *c;
@@ -375,7 +400,7 @@ static void getmoreargs(const char *partial, const char *mprompt)
 
 void setpeer(int argc, char *argv[])
 {
-    struct hostent *host;
+    int err;
 
     if (argc < 2) {
         getmoreargs("connect ", "(to) ");
@@ -388,16 +413,34 @@ void setpeer(int argc, char *argv[])
         return;
     }
 
-    host = gethostbyname(argv[1]);
-    if (host == 0) {
+    peeraddr.sa.sa_family = ai_fam;
+    err = set_sock_addr(argv[1], &peeraddr, &hostname);
+    if (err) {
         connected = 0;
-        printf("%s: unknown host\n", argv[1]);
         return;
     }
-    peeraddr.sin_family = host->h_addrtype;
-    bcopy(host->h_addr, &peeraddr.sin_addr, host->h_length);
-    hostname = xstrdup(host->h_name);
-
+    ai_fam = peeraddr.sa.sa_family;
+    if (f == -1) { /* socket not open */
+        ai_fam_sock = ai_fam;
+    } else { /* socket was already open */
+        if (ai_fam_sock != ai_fam) { /* need reopen socken for new family */
+            union sock_addr sa;
+
+            close(f);
+            ai_fam_sock = ai_fam;
+            f = socket(ai_fam_sock, SOCK_DGRAM, 0);
+            if (f < 0) {
+                perror("tftp: socket");
+                exit(EX_OSERR);
+            }
+            bzero((char *)&sa, sizeof (sa));
+            sa.sa.sa_family = ai_fam_sock;
+            if (pick_port_bind(f, &sa, portrange_from, portrange_to)) {
+                perror("tftp: bind");
+                exit(EX_OSERR);
+            }
+        }
+    }
     port = sp->s_port;
     if (argc == 3) {
         struct servent *usp;
@@ -418,9 +461,13 @@ void setpeer(int argc, char *argv[])
     }
 
     if (verbose) {
+        char tmp[INET6_ADDRSTRLEN], *tp;
+        tp = (char *)inet_ntop(peeraddr.sa.sa_family, SOCKADDR_P(&peeraddr),
+                               tmp, INET6_ADDRSTRLEN);
+        if (!tp)
+            tp = (char *)"???";
         printf("Connected to %s (%s), port %u\n",
-               hostname, inet_ntoa(peeraddr.sin_addr),
-               (unsigned int)ntohs(port));
+               hostname, tp, (unsigned int)ntohs(port));
     }
     connected = 1;
 }
@@ -484,7 +531,7 @@ static void settftpmode(const struct modes *newmode)
 void put(int argc, char *argv[])
 {
     int fd;
-    int n;
+    int n, err;
     char *cp, *targ;
 
     if (argc < 2) {
@@ -499,8 +546,6 @@ void put(int argc, char *argv[])
     }
     targ = argv[argc - 1];
     if (!literal && strchr(argv[argc - 1], ':')) {
-        struct hostent *hp;
-
         for (n = 1; n < argc - 1; n++)
             if (strchr(argv[n], ':')) {
                 putusage(argv[0]);
@@ -509,16 +554,14 @@ void put(int argc, char *argv[])
         cp = argv[argc - 1];
         targ = strchr(cp, ':');
         *targ++ = 0;
-        hp = gethostbyname(cp);
-        if (hp == NULL) {
-            fprintf(stderr, "tftp: %s: ", cp);
-            herror((char *)NULL);
+        peeraddr.sa.sa_family = ai_fam;
+        err = set_sock_addr(cp, &peeraddr,&hostname);
+        if (err) {
+            connected = 0;
             return;
         }
-        bcopy(hp->h_addr, &peeraddr.sin_addr, hp->h_length);
-        peeraddr.sin_family = hp->h_addrtype;
+        ai_fam = peeraddr.sa.sa_family;
         connected = 1;
-        hostname = xstrdup(hp->h_name);
     }
     if (!connected) {
         printf("No target machine specified.\n");
@@ -535,7 +578,7 @@ void put(int argc, char *argv[])
         if (verbose)
             printf("putting %s to %s:%s [%s]\n",
                    cp, hostname, targ, mode->m_mode);
-        peeraddr.sin_port = port;
+        sa_set_port(&peeraddr, port);
         tftp_sendfile(fd, targ, mode->m_mode);
         return;
     }
@@ -554,7 +597,7 @@ void put(int argc, char *argv[])
         if (verbose)
             printf("putting %s to %s:%s [%s]\n",
                    argv[n], hostname, targ, mode->m_mode);
-        peeraddr.sin_port = port;
+        sa_set_port(&peeraddr, port);
         tftp_sendfile(fd, targ, mode->m_mode);
     }
 }
@@ -597,19 +640,15 @@ void get(int argc, char *argv[])
         if (literal || src == NULL)
             src = argv[n];
         else {
-            struct hostent *hp;
+            int err;
 
             *src++ = 0;
-            hp = gethostbyname(argv[n]);
-            if (hp == NULL) {
-                fprintf(stderr, "tftp: %s: ", argv[n]);
-                herror((char *)NULL);
+            peeraddr.sa.sa_family = ai_fam;
+            err = set_sock_addr(argv[n], &peeraddr, &hostname);
+            if (err)
                 continue;
-            }
-            bcopy(hp->h_addr, (caddr_t) & peeraddr.sin_addr, hp->h_length);
-            peeraddr.sin_family = hp->h_addrtype;
+            ai_fam = peeraddr.sa.sa_family;
             connected = 1;
-            hostname = xstrdup(hp->h_name);
         }
         if (argc < 4) {
             cp = argc == 3 ? argv[2] : tail(src);
@@ -623,7 +662,7 @@ void get(int argc, char *argv[])
             if (verbose)
                 printf("getting from %s:%s to %s [%s]\n",
                        hostname, src, cp, mode->m_mode);
-            peeraddr.sin_port = port;
+            sa_set_port(&peeraddr, port);
             tftp_recvfile(fd, src, mode->m_mode);
             break;
         }
@@ -638,7 +677,7 @@ void get(int argc, char *argv[])
         if (verbose)
             printf("getting from %s:%s to %s [%s]\n",
                    hostname, src, cp, mode->m_mode);
-        peeraddr.sin_port = port;
+        sa_set_port(&peeraddr, port);
         tftp_recvfile(fd, src, mode->m_mode);
     }
 }
diff --git a/tftp/tftp.1.in b/tftp/tftp.1.in
index 8ef1e86..8bbb796 100644
--- a/tftp/tftp.1.in
+++ b/tftp/tftp.1.in
@@ -42,7 +42,7 @@
 .br
 .SH DESCRIPTION
 .B tftp
-is a client for the IPv4 Trivial file Transfer Protocol, which can be
+is a client for the Trivial file Transfer Protocol, which can be
 used to transfer files to and from remote machines, including some
 very minimalistic, usually embedded, systems.  The remote
 .I host
@@ -55,6 +55,11 @@ as the default host for future transfers (see the
 command below.)
 .SH OPTIONS
 .TP
+.B \-4
+Connect with IPv4 only, if IPv6 support was compiled in.
+.TP
+.B \-6
+.TP
 \fB\-c\fP \fIcommand\fP
 Execute \fIcommand\fP as if it had been entered on the tftp prompt.
 Must be specified last on the command line.
diff --git a/tftp/tftp.c b/tftp/tftp.c
index 2d26b4b..d15da22 100644
--- a/tftp/tftp.c
+++ b/tftp/tftp.c
@@ -38,8 +38,8 @@
  */
 #include "extern.h"
 
-extern struct sockaddr_in peeraddr;     /* filled in by main */
-extern int f;                   /* the opened socket */
+extern union sock_addr peeraddr; /* filled in by main */
+extern int f;                    /* the opened socket */
 extern int trace;
 extern int verbose;
 extern int rexmtval;
@@ -71,7 +71,7 @@ void tftp_sendfile(int fd, const char *name, const char *mode)
     volatile u_short block;
     volatile int size, convert;
     volatile off_t amount;
-    struct sockaddr_in from;
+    union sock_addr from;
     socklen_t fromlen;
     FILE *file;
     u_short ap_opcode, ap_block;
@@ -105,7 +105,7 @@ void tftp_sendfile(int fd, const char *name, const char *mode)
         if (trace)
             tpacket("sent", dp, size + 4);
         n = sendto(f, dp, size + 4, 0,
-                   (struct sockaddr *)&peeraddr, sizeof(peeraddr));
+                   &peeraddr.sa, SOCKLEN(&peeraddr));
         if (n != size + 4) {
             perror("tftp: sendto");
             goto abort;
@@ -116,14 +116,14 @@ void tftp_sendfile(int fd, const char *name, const char *mode)
             do {
                 fromlen = sizeof(from);
                 n = recvfrom(f, ackbuf, sizeof(ackbuf), 0,
-                             (struct sockaddr *)&from, &fromlen);
+                             &from.sa, &fromlen);
             } while (n <= 0);
             alarm(0);
             if (n < 0) {
                 perror("tftp: recvfrom");
                 goto abort;
             }
-            peeraddr.sin_port = from.sin_port;  /* added */
+            sa_set_port(&peeraddr, SOCKPORT(&from));  /* added */
             if (trace)
                 tpacket("received", ap, n);
             /* should verify packet came from server */
@@ -176,7 +176,7 @@ void tftp_recvfile(int fd, const char *name, const char *mode)
     volatile u_short block;
     volatile int size, firsttrip;
     volatile unsigned long amount;
-    struct sockaddr_in from;
+    union sock_addr from;
     socklen_t fromlen;
     FILE *file;
     volatile int convert;       /* true if converting crlf -> lf */
@@ -207,8 +207,8 @@ void tftp_recvfile(int fd, const char *name, const char *mode)
       send_ack:
         if (trace)
             tpacket("sent", ap, size);
-        if (sendto(f, ackbuf, size, 0, (struct sockaddr *)&peeraddr,
-                   sizeof(peeraddr)) != size) {
+        if (sendto(f, ackbuf, size, 0, &peeraddr.sa,
+                   SOCKLEN(&peeraddr)) != size) {
             alarm(0);
             perror("tftp: sendto");
             goto abort;
@@ -219,14 +219,14 @@ void tftp_recvfile(int fd, const char *name, const char *mode)
             do {
                 fromlen = sizeof(from);
                 n = recvfrom(f, dp, PKTSIZE, 0,
-                             (struct sockaddr *)&from, &fromlen);
+                             &from.sa, &fromlen);
             } while (n <= 0);
             alarm(0);
             if (n < 0) {
                 perror("tftp: recvfrom");
                 goto abort;
             }
-            peeraddr.sin_port = from.sin_port;  /* added */
+            sa_set_port(&peeraddr, SOCKPORT(&from));  /* added */
             if (trace)
                 tpacket("received", dp, n);
             /* should verify client address */
@@ -266,7 +266,7 @@ void tftp_recvfile(int fd, const char *name, const char *mode)
     ap->th_opcode = htons((u_short) ACK);       /* has seen err msg */
     ap->th_block = htons((u_short) block);
     (void)sendto(f, ackbuf, 4, 0, (struct sockaddr *)&peeraddr,
-                 sizeof(peeraddr));
+                 SOCKLEN(&peeraddr));
     write_behind(file, convert);        /* flush last buffer */
     fclose(file);
     stopclock();
@@ -341,8 +341,8 @@ static void nak(int error, const char *msg)
 
     if (trace)
         tpacket("sent", tp, length);
-    if (sendto(f, ackbuf, length, 0, (struct sockaddr *)&peeraddr,
-               sizeof(peeraddr)) != length)
+    if (sendto(f, ackbuf, length, 0, &peeraddr.sa,
+               SOCKLEN(&peeraddr)) != length)
         perror("nak");
 }
 
diff --git a/tftpd/recvfrom.c b/tftpd/recvfrom.c
index fee6d03..389ba82 100644
--- a/tftpd/recvfrom.c
+++ b/tftpd/recvfrom.c
@@ -18,8 +18,8 @@
  */
 
 #include "config.h"             /* Must be included first! */
-#include "recvfrom.h"
 #include "common/tftpsubs.h"
+#include "recvfrom.h"
 #ifdef HAVE_MACHINE_PARAM_H
 #include <machine/param.h>      /* Needed on some versions of FreeBSD */
 #endif
@@ -55,31 +55,47 @@ struct in_pktinfo {
  * end up having the same local and remote address when trying to
  * bind to it.
  */
-static int address_is_local(const struct sockaddr_in *addr)
+static int address_is_local(const union sock_addr *addr)
 {
-    struct sockaddr_in sin;
+    union sock_addr sa;
     int sockfd = -1;
     int e;
     int rv = 0;
     socklen_t addrlen;
 
     /* Multicast or universal broadcast address? */
-    if (ntohl(addr->sin_addr.s_addr) >= (224UL << 24))
+    if (addr->sa.sa_family == AF_INET) {
+        if (ntohl(addr->si.sin_addr.s_addr) >= (224UL << 24))
+            return 0;
+    }
+#ifdef HAVE_IPV6
+    else if (addr->sa.sa_family == AF_INET6) {
+        if (IN6_IS_ADDR_MULTICAST(&addr->s6.sin6_addr))
+            return 0;
+    }
+#endif
+    else
         return 0;
 
-    sockfd = socket(PF_INET, SOCK_DGRAM, 0);
+    sockfd = socket(addr->sa.sa_family, SOCK_DGRAM, 0);
     if (sockfd < 0)
         goto err;
 
-    if (connect(sockfd, (const struct sockaddr *)addr, sizeof *addr))
+    if (connect(sockfd, &addr->sa, SOCKLEN(addr)))
         goto err;
 
-    addrlen = sizeof sin;
-    if (getsockname(sockfd, (struct sockaddr *)&sin, &addrlen))
+    addrlen = SOCKLEN(addr);
+    if (getsockname(sockfd, (struct sockaddr *)&sa, &addrlen))
         goto err;
 
-    rv = sin.sin_addr.s_addr == addr->sin_addr.s_addr;
-
+    if (addr->sa.sa_family == AF_INET)
+        rv = sa.si.sin_addr.s_addr == addr->si.sin_addr.s_addr;
+#ifdef HAVE_IPV6
+    else if (addr->sa.sa_family == AF_INET6)
+        rv = IN6_ARE_ADDR_EQUAL(&sa.s6.sin6_addr, &addr->s6.sin6_addr);
+#endif
+    else
+        rv = 0;
   err:
     e = errno;
 
@@ -93,7 +109,7 @@ static int address_is_local(const struct sockaddr_in *addr)
 int
 myrecvfrom(int s, void *buf, int len, unsigned int flags,
            struct sockaddr *from, socklen_t * fromlen,
-           struct sockaddr_in *myaddr)
+           union sock_addr *myaddr)
 {
     struct msghdr msg;
     struct iovec iov;
@@ -107,23 +123,41 @@ myrecvfrom(int s, void *buf, int len, unsigned int flags,
 #else
         char control[CMSG_SPACE(sizeof(struct in_addr))];
 #endif
+#ifdef HAVE_IPV6
+#ifdef HAVE_STRUCT_IN6_PKTINFO
+        char control6[CMSG_SPACE(sizeof(struct in6_addr)) +
+                     CMSG_SPACE(sizeof(struct in6_pktinfo))];
+#else
+        char control6[CMSG_SPACE(sizeof(struct in6_addr))];
+#endif
+#endif
     } control_un;
     int on = 1;
 #ifdef IP_PKTINFO
     struct in_pktinfo pktinfo;
 #endif
+#ifdef HAVE_STRUCT_IN6_PKTINFO
+    struct in6_pktinfo pktinfo6;
+#endif
 
     /* Try to enable getting the return address */
 #ifdef IP_RECVDSTADDR
-    setsockopt(s, IPPROTO_IP, IP_RECVDSTADDR, &on, sizeof(on));
+    if (from->sa_family == AF_INET)
+        setsockopt(s, IPPROTO_IP, IP_RECVDSTADDR, &on, sizeof(on));
 #endif
 #ifdef IP_PKTINFO
-    setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on));
+    if (from->sa_family == AF_INET)
+        setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on));
+#endif
+#ifdef HAVE_IPV6
+#ifdef IPV6_RECVPKTINFO
+    if (from->sa_family == AF_INET6)
+        setsockopt(s, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on, sizeof(on));
+#endif
 #endif
-
     bzero(&msg, sizeof msg);    /* Clear possible system-dependent fields */
     msg.msg_control = control_un.control;
-    msg.msg_controllen = sizeof(control_un.control);
+    msg.msg_controllen = sizeof(control_un);
     msg.msg_flags = 0;
 
     msg.msg_name = from;
@@ -139,8 +173,8 @@ myrecvfrom(int s, void *buf, int len, unsigned int flags,
     *fromlen = msg.msg_namelen;
 
     if (myaddr) {
-        bzero(myaddr, sizeof(struct sockaddr_in));
-        myaddr->sin_family = AF_INET;
+        bzero(myaddr, sizeof(*myaddr));
+        myaddr->sa.sa_family = from->sa_family;
 
         if (msg.msg_controllen < sizeof(struct cmsghdr) ||
             (msg.msg_flags & MSG_CTRUNC))
@@ -149,31 +183,61 @@ myrecvfrom(int s, void *buf, int len, unsigned int flags,
         for (cmptr = CMSG_FIRSTHDR(&msg); cmptr != NULL;
              cmptr = CMSG_NXTHDR(&msg, cmptr)) {
 
+            if (from->sa_family == AF_INET) {
+                myaddr->sa.sa_family = AF_INET;
 #ifdef IP_RECVDSTADDR
-            if (cmptr->cmsg_level == IPPROTO_IP &&
-                cmptr->cmsg_type == IP_RECVDSTADDR) {
-                memcpy(&myaddr->sin_addr, CMSG_DATA(cmptr),
-                       sizeof(struct in_addr));
-            }
+                if (cmptr->cmsg_level == IPPROTO_IP &&
+                    cmptr->cmsg_type == IP_RECVDSTADDR) {
+                    memcpy(&myaddr->si.sin_addr, CMSG_DATA(cmptr),
+                           sizeof(struct in_addr));
+                }
 #endif
 
 #ifdef IP_PKTINFO
-            if (cmptr->cmsg_level == IPPROTO_IP &&
-                cmptr->cmsg_type == IP_PKTINFO) {
-                memcpy(&pktinfo, CMSG_DATA(cmptr),
-                       sizeof(struct in_pktinfo));
-                memcpy(&myaddr->sin_addr, &pktinfo.ipi_addr,
-                       sizeof(struct in_addr));
+                if (cmptr->cmsg_level == IPPROTO_IP &&
+                    cmptr->cmsg_type == IP_PKTINFO) {
+                    memcpy(&pktinfo, CMSG_DATA(cmptr),
+                           sizeof(struct in_pktinfo));
+                    memcpy(&myaddr->si.sin_addr, &pktinfo.ipi_addr,
+                           sizeof(struct in_addr));
+                }
+#endif
             }
+#ifdef HAVE_IPV6
+            else if (from->sa_family == AF_INET6) {
+                myaddr->sa.sa_family = AF_INET6;
+#ifdef IP6_RECVDSTADDR
+                if (cmptr->cmsg_level == IPPROTO_IPV6 &&
+                    cmptr->cmsg_type == IPV6_RECVDSTADDR )
+                    memcpy(&myaddr->s6.sin6_addr, CMSG_DATA(cmptr),
+                           sizeof(struct in6_addr));
 #endif
 
+#ifdef HAVE_STRUCT_IN6_PKTINFO
+                if (cmptr->cmsg_level == IPPROTO_IPV6 &&
+                    (cmptr->cmsg_type == IPV6_RECVPKTINFO ||
+                     cmptr->cmsg_type == IPV6_PKTINFO)) {
+                    memcpy(&pktinfo6, CMSG_DATA(cmptr),
+                           sizeof(struct in6_pktinfo));
+                    memcpy(&myaddr->s6.sin6_addr, &pktinfo6.ipi6_addr,
+                           sizeof(struct in6_addr));
+                }
+#endif
+            }
+#endif
+        }
+        /* If the address is not a valid local address,
+         * then bind to any address...
+         */
+        if (address_is_local(myaddr) != 1) {
+            if (myaddr->sa.sa_family == AF_INET)
+                ((struct sockaddr_in *)myaddr)->sin_addr.s_addr = INADDR_ANY;
+#ifdef HAVE_IPV6
+            else if (myaddr->sa.sa_family == AF_INET6)
+                memset(&myaddr->s6.sin6_addr, 0, sizeof(struct in6_addr));
+#endif
         }
     }
-
-    /* If the address is not a valid local address, then bind to any address... */
-    if (address_is_local(myaddr) != 1)
-        myaddr->sin_addr.s_addr = INADDR_ANY;
-
     return n;
 }
 
@@ -181,15 +245,13 @@ myrecvfrom(int s, void *buf, int len, unsigned int flags,
 
 int
 myrecvfrom(int s, void *buf, int len, unsigned int flags,
-           struct sockaddr *from, int *fromlen, struct sockaddr_in *myaddr)
+           struct sockaddr *from, int *fromlen, union sock_addr *myaddr)
 {
     /* There is no way we can get the local address, fudge it */
 
-    bzero(myaddr, sizeof(struct sockaddr_in));
-    myaddr->sin_family = AF_INET;
-
-    myaddr->sin_port = htons(IPPORT_TFTP);
-    bzero(&myaddr->sin_addr, sizeof(myaddr->sin_addr));
+    bzero(myaddr, sizeof(*myaddr));
+    myaddr->sa.sa_family = from->sa_family;
+    sa_set_port(myaddr, htons(IPPORT_TFTP));
 
     return recvfrom(s, buf, len, flags, from, fromlen);
 }
diff --git a/tftpd/recvfrom.h b/tftpd/recvfrom.h
index fda65c0..e3c4055 100644
--- a/tftpd/recvfrom.h
+++ b/tftpd/recvfrom.h
@@ -19,5 +19,5 @@
 
 int
 myrecvfrom(int s, void *buf, int len, unsigned int flags,
-           struct sockaddr *from, socklen_t * fromlen,
-           struct sockaddr_in *myaddr);
+           struct sockaddr *from, socklen_t *fromlen,
+           union sock_addr *myaddr);
diff --git a/tftpd/tftpd.8.in b/tftpd/tftpd.8.in
index 49cf359..b4d1ac3 100644
--- a/tftpd/tftpd.8.in
+++ b/tftpd/tftpd.8.in
@@ -40,7 +40,7 @@
 .I directory...
 .SH DESCRIPTION
 .B tftpd
-is a server for the IPv4 Trivial File Transfer Protocol.  The TFTP
+is a server for the Trivial File Transfer Protocol.  The TFTP
 protocol is extensively used to support remote booting of diskless
 devices.  The server is normally started by
 .BR inetd ,
@@ -48,6 +48,12 @@ but can also run standalone.
 .PP
 .SH OPTIONS
 .TP
+.B \-4
+Connect with IPv4 only, if IPv6 support was compiled in.
+.TP
+.B \-6
+Connect with IPv6 only, if IPv6 support was compiled in.
+.TP
 .B \-l
 Run the server in standalone (listen) mode, rather than run from
 .BR inetd .
diff --git a/tftpd/tftpd.c b/tftpd/tftpd.c
index b5798a6..38f5e7b 100644
--- a/tftpd/tftpd.c
+++ b/tftpd/tftpd.c
@@ -42,7 +42,6 @@
 
 #include <sys/ioctl.h>
 #include <signal.h>
-#include <netdb.h>
 #include <ctype.h>
 #include <pwd.h>
 #include <limits.h>
@@ -65,6 +64,12 @@ int allow_severity = -1;        /* Don't log at all */
 struct request_info wrap_request;
 #endif
 
+#ifdef HAVE_IPV6
+int ai_fam = AF_UNSPEC;
+#else
+int ai_fam = AF_INET;
+#endif
+
 #define	TIMEOUT 1000000         /* Default timeout (us) */
 #define TRIES   6               /* Number of attempts to send each packet */
 #define TIMEOUT_LIMIT ((1 << TRIES)-1)
@@ -82,7 +87,9 @@ char buf[PKTSIZE];
 char ackbuf[PKTSIZE];
 unsigned int max_blksize = MAX_SEGSIZE;
 
-struct sockaddr_in from;
+char tmpbuf[INET6_ADDRSTRLEN], *tmp_p;
+
+union sock_addr from;
 socklen_t fromlen;
 off_t tsize;
 int tsize_ok;
@@ -254,10 +261,16 @@ int main(int argc, char **argv)
     struct tftphdr *tp;
     struct passwd *pw;
     struct options *opt;
-    struct sockaddr_in myaddr;
-    struct sockaddr_in bindaddr;
+    union sock_addr myaddr;
+    struct sockaddr_in bindaddr4;
+#ifdef HAVE_IPV6
+    struct sockaddr_in6 bindaddr6;
+#endif
     int n;
-    int fd = 0;
+    int fd = -1;
+    int fd4 = -1;
+    int fd6 = -1;
+    int fdmax = 0;
     int standalone = 0;         /* Standalone (listen) mode */
     int nodaemon = 0;           /* Do not detach process */
     char *address = NULL;       /* Address to listen to */
@@ -283,8 +296,16 @@ int main(int argc, char **argv)
 
     srand(time(NULL) ^ getpid());
 
-    while ((c = getopt(argc, argv, "cspvVlLa:B:u:U:r:t:T:R:m:")) != -1)
+    while ((c = getopt(argc, argv, "46cspvVlLa:B:u:U:r:t:T:R:m:")) != -1)
         switch (c) {
+#ifdef HAVE_IPV6
+        case '4':
+            ai_fam = AF_INET;
+            break;
+        case '6':
+            ai_fam = AF_INET6;
+            break;
+#endif
         case 'c':
             cancreate = 1;
             break;
@@ -417,12 +438,6 @@ int main(int argc, char **argv)
     if (spec_umask || !unixperms)
         umask(my_umask);
 
-    /* Note: on Cygwin, select() on a nonblocking socket becomes
-       a nonblocking select. */
-#ifndef __CYGWIN__
-    set_socket_nonblock(fd, 1);
-#endif
-
 #ifdef WITH_REGEX
     if (rewrite_file)
         rewrite_rules = read_remap_rules(rewrite_file);
@@ -430,16 +445,45 @@ int main(int argc, char **argv)
 
     /* If we're running standalone, set up the input port */
     if (standalone) {
-        fd = socket(PF_INET, SOCK_DGRAM, 0);
-
-        memset(&bindaddr, 0, sizeof bindaddr);
-        bindaddr.sin_family = AF_INET;
-        bindaddr.sin_addr.s_addr = INADDR_ANY;
-        bindaddr.sin_port = htons(IPPORT_TFTP);
-
+#ifdef HAVE_IPV6
+        if (ai_fam != AF_INET6) {
+#endif
+            fd4 = socket(AF_INET, SOCK_DGRAM, 0);
+            if (fd4 < 0) {
+                syslog(LOG_ERR, "cannot open IPv4 socket: %m");
+                exit(EX_OSERR);
+            }
+#ifndef __CYGWIN__
+            set_socket_nonblock(fd4, 1);
+#endif
+            memset(&bindaddr4, 0, sizeof bindaddr4);
+            bindaddr4.sin_family = AF_INET;
+            bindaddr4.sin_addr.s_addr = INADDR_ANY;
+            bindaddr4.sin_port = htons(IPPORT_TFTP);
+#ifdef HAVE_IPV6
+        }
+        if (ai_fam != AF_INET) {
+            fd6 = socket(AF_INET6, SOCK_DGRAM, 0);
+            if (fd6 < 0) {
+                if (fd4 < 0) {
+                    syslog(LOG_ERR, "cannot open IPv6 socket: %m");
+                    exit(EX_OSERR);
+                } else {
+                    syslog(LOG_ERR,
+                           "cannot open IPv6 socket, disable IPv6: %m");
+                }
+            }
+#ifndef __CYGWIN__
+            set_socket_nonblock(fd6, 1);
+#endif
+            memset(&bindaddr6, 0, sizeof bindaddr6);
+            bindaddr6.sin6_family = AF_INET6;
+            bindaddr6.sin6_port = htons(IPPORT_TFTP);
+        }
+#endif
         if (address) {
             char *portptr, *eportptr;
-            struct hostent *hostent;
+            int err;
             struct servent *servent;
             unsigned long port;
 
@@ -447,17 +491,40 @@ int main(int argc, char **argv)
             portptr = strrchr(address, ':');
             if (portptr)
                 *portptr++ = '\0';
-
+            else
+                portptr = (char *)"tftp";
             if (*address) {
-                hostent = gethostbyname(address);
-                if (!hostent || hostent->h_addrtype != AF_INET) {
-                    syslog(LOG_ERR,
-                           "cannot resolve local bind address: %s",
-                           address);
-                    exit(EX_NOINPUT);
+                if (fd4 >= 0) {
+                    bindaddr4.sin_family = AF_INET;
+                    err = set_sock_addr(address,
+                                        (union sock_addr *)&bindaddr4, NULL);
+                    if (err) {
+                        syslog(LOG_ERR,
+                               "cannot resolve local IPv4 bind address: %s",
+                               address);
+                        exit(EX_NOINPUT);
+                    }
+                }
+#ifdef HAVE_IPV6
+                if (fd6 >= 0) {
+                    err = set_sock_addr(address,
+                                        (union sock_addr *)&bindaddr6, NULL);
+                    if (err) {
+                        if (fd4 >= 0) {
+                            syslog(LOG_ERR,
+                                   "cannot resolve local IPv6 bind address: %s"
+                                   "; using IPv4 only", address);
+                            close(fd6);
+                            fd6 = -1;
+                        } else {
+                            syslog(LOG_ERR,
+                                   "cannot resolve local IPv6 bind address: %s",
+                                   address);
+                            exit(EX_NOINPUT);
+                        }
+                    }
                 }
-                memcpy(&bindaddr.sin_addr, hostent->h_addr,
-                       hostent->h_length);
+#endif
             } else {
                 /* Default to using INADDR_ANY */
             }
@@ -465,10 +532,20 @@ int main(int argc, char **argv)
             if (portptr && *portptr) {
                 servent = getservbyname(portptr, "udp");
                 if (servent) {
-                    bindaddr.sin_port = servent->s_port;
+                    if (fd4 >= 0)
+                        bindaddr4.sin_port = servent->s_port;
+#ifdef HAVE_IPV6
+                    if (fd6 >= 0)
+                        bindaddr6.sin6_port = servent->s_port;
+#endif
                 } else if ((port = strtoul(portptr, &eportptr, 0))
                            && !*eportptr) {
-                    bindaddr.sin_port = htons(port);
+                    if (fd4 >= 0)
+                        bindaddr4.sin_port = htons(port);
+#ifdef HAVE_IPV6
+                    if (fd6 >= 0)
+                        bindaddr6.sin6_port = htons(port);
+#endif
                 } else if (!strcmp(portptr, "tftp")) {
                     /* It's TFTP, we're OK */
                 } else {
@@ -479,11 +556,37 @@ int main(int argc, char **argv)
             }
         }
 
-        if (bind(fd, (struct sockaddr *)&bindaddr, sizeof bindaddr) < 0) {
-            syslog(LOG_ERR, "cannot bind to local socket: %m");
-            exit(EX_OSERR);
+        if (fd4 >= 0) {
+            if (bind(fd4, (struct sockaddr *)&bindaddr4,
+              sizeof(bindaddr4)) < 0) {
+                syslog(LOG_ERR, "cannot bind to local IPv4 socket: %m");
+                exit(EX_OSERR);
+            }
         }
-
+#ifdef HAVE_IPV6
+        if (fd6 >= 0) {
+            int on = 1;
+#if defined(IPV6_V6ONLY)
+            if (setsockopt(fd6, IPPROTO_IPV6, IPV6_V6ONLY, (char*)&on,
+              sizeof(on))) {
+                syslog(LOG_ERR, "cannot setsockopt IPV6_V6ONLY %m");
+            }
+#endif
+            if (bind(fd6, (struct sockaddr *)&bindaddr6,
+              sizeof(bindaddr6)) < 0) {
+                if (fd4 >= 0) {
+                    syslog(LOG_ERR,
+                           "cannot bind to local IPv6 socket,"
+                           "IPv6 disabled: %m");
+                    close(fd6);
+                    fd6 = -1;
+                } else {
+                    syslog(LOG_ERR, "cannot bind to local IPv6 socket: %m");
+                    exit(EX_OSERR);
+                }
+            }
+        }
+#endif
         /* Daemonize this process */
         /* Note: when running in secure mode (-s), we must not chroot, since
            we are already in the proper directory. */
@@ -491,10 +594,21 @@ int main(int argc, char **argv)
             syslog(LOG_ERR, "cannot daemonize: %m");
             exit(EX_OSERR);
         }
+        if (fd6 > fd4)
+            fdmax = fd6;
+        else
+            fdmax = fd4;
     } else {
         /* 0 is our socket descriptor */
         close(1);
         close(2);
+        fd = 0;
+        fdmax = 0;
+        /* Note: on Cygwin, select() on a nonblocking socket becomes
+           a nonblocking select. */
+#ifndef __CYGWIN__
+        set_socket_nonblock(fd, 1);
+#endif
     }
 
     /* Disable path MTU discovery */
@@ -533,29 +647,61 @@ int main(int argc, char **argv)
         }
 
         FD_ZERO(&readset);
-        FD_SET(fd, &readset);
+        if (standalone) {
+            if (fd4 >= 0) {
+                FD_SET(fd4, &readset);
+#ifdef __CYGWIN__
+                /* On Cygwin, select() on a nonblocking socket returns
+                   immediately, with a rv of 0! */
+                set_socket_nonblock(fd4, 0);
+#endif
+            }
+            if (fd6 >= 0) {
+                FD_SET(fd6, &readset);
+#ifdef __CYGWIN__
+                /* On Cygwin, select() on a nonblocking socket returns
+                   immediately, with a rv of 0! */
+                set_socket_nonblock(fd6, 0);
+#endif
+            }
+        } else { /* fd always 0 */
+            fd = 0;
+#ifdef __CYGWIN__
+            /* On Cygwin, select() on a nonblocking socket returns
+               immediately, with a rv of 0! */
+            set_socket_nonblock(fd, 0);
+#endif
+            FD_SET(fd, &readset);
+        }
         tv_waittime.tv_sec = waittime;
         tv_waittime.tv_usec = 0;
 
-#ifdef __CYGWIN__
-        /* On Cygwin, select() on a nonblocking socket returns immediately,
-           with a rv of 0! */
-        set_socket_nonblock(fd, 0);
-#endif
 
         /* Never time out if we're in standalone mode */
-        rv = select(fd + 1, &readset, NULL, NULL,
+        rv = select(fdmax + 1, &readset, NULL, NULL,
                     standalone ? NULL : &tv_waittime);
         if (rv == -1 && errno == EINTR)
             continue;           /* Signal caught, reloop */
+
         if (rv == -1) {
             syslog(LOG_ERR, "select loop: %m");
             exit(EX_IOERR);
         } else if (rv == 0) {
             exit(0);            /* Timeout, return to inetd */
         }
+
+        if (standalone) {
+            if ((fd4 >= 0) && FD_ISSET(fd4, &readset))
+                fd = fd4;
+            else if ((fd6 >= 0) && FD_ISSET(fd6, &readset))
+                fd = fd6;
+            else /* not in set ??? */
+                continue;
+        }
 #ifdef __CYGWIN__
-        set_socket_nonblock(fd, 1);
+        /* On Cygwin, select() on a nonblocking socket returns
+           immediately, with a rv of 0! */
+        set_socket_nonblock(fd, 0);
 #endif
 
         fromlen = sizeof(from);
@@ -570,18 +716,32 @@ int main(int argc, char **argv)
                 exit(EX_IOERR);
             }
         }
-
-        if (from.sin_family != AF_INET) {
-            syslog(LOG_ERR,
-                   "received address was not AF_INET, please check your inetd config");
+#ifdef HAVE_IPV6
+        if ((from.sa.sa_family != AF_INET) && (from.sa.sa_family != AF_INET6)) {
+            syslog(LOG_ERR, "received address was not AF_INET/AF_INET6,"
+                   " please check your inetd config");
+#else
+        if (from.sa.sa_family != AF_INET) {
+            syslog(LOG_ERR, "received address was not AF_INET,"
+                   " please check your inetd config");
+#endif
             exit(EX_PROTOCOL);
         }
 
-        if (standalone && myaddr.sin_addr.s_addr == INADDR_ANY) {
-            /* myrecvfrom() didn't capture the source address; but we might
-               have bound to a specific address, if so we should use it */
-            memcpy(&myaddr.sin_addr, &bindaddr.sin_addr,
-                   sizeof bindaddr.sin_addr);
+        if (standalone) {
+            if ((from.sa.sa_family == AF_INET) &&
+              (myaddr.si.sin_addr.s_addr == INADDR_ANY)) {
+                /* myrecvfrom() didn't capture the source address; but we might
+                   have bound to a specific address, if so we should use it */
+                memcpy(SOCKADDR_P(&myaddr), &bindaddr4.sin_addr,
+                       sizeof(bindaddr4.sin_addr));
+#ifdef HAVE_IPV6
+            } else if ((from.sa.sa_family == AF_INET6) &&
+              IN6_IS_ADDR_UNSPECIFIED(SOCKADDR_P(&myaddr))) {
+                memcpy(SOCKADDR_P(&myaddr), &bindaddr6.sin6_addr,
+                       sizeof(bindaddr6.sin6_addr));
+#endif
+            }
         }
 
         /*
@@ -609,14 +769,19 @@ int main(int argc, char **argv)
                  RQ_FILE, fd,
                  RQ_CLIENT_SIN, &from, RQ_SERVER_SIN, &myaddr, 0);
     sock_methods(&wrap_request);
+
+    tmp_p = (char *)inet_ntop(myaddr.sa.sa_family, SOCKADDR_P(&myaddr),
+                              tmpbuf, INET6_ADDRSTRLEN);
+    if (!tmp_p) {
+        tmp_p = tmpbuf;
+        strcpy(tmpbuf, "???");
+    }
     if (hosts_access(&wrap_request) == 0) {
         if (deny_severity != -1)
-            syslog(deny_severity, "connection refused from %s",
-                   inet_ntoa(from.sin_addr));
+            syslog(deny_severity, "connection refused from %s", tmp_p);
         exit(EX_NOPERM);        /* Access denied */
     } else if (allow_severity != -1) {
-        syslog(allow_severity, "connect from %s",
-               inet_ntoa(from.sin_addr));
+        syslog(allow_severity, "connect from %s", tmp_p);
     }
 #endif
 
@@ -626,7 +791,7 @@ int main(int argc, char **argv)
     /* Get a socket.  This has to be done before the chroot(), since
        some systems require access to /dev to create a socket. */
 
-    peer = socket(AF_INET, SOCK_DGRAM, 0);
+    peer = socket(myaddr.sa.sa_family, SOCK_DGRAM, 0);
     if (peer < 0) {
         syslog(LOG_ERR, "socket: %m");
         exit(EX_IOERR);
@@ -677,16 +842,13 @@ int main(int argc, char **argv)
         exit(EX_OSERR);
     }
 
-    /* Other basic setup */
-    from.sin_family = AF_INET;
-
     /* Process the request... */
     if (pick_port_bind(peer, &myaddr, portrange_from, portrange_to) < 0) {
         syslog(LOG_ERR, "bind: %m");
         exit(EX_IOERR);
     }
 
-    if (connect(peer, (struct sockaddr *)&from, sizeof from) < 0) {
+    if (connect(peer, &from.sa, SOCKLEN(&from)) < 0) {
         syslog(LOG_ERR, "connect: %m");
         exit(EX_IOERR);
     }
@@ -776,16 +938,22 @@ int tftp(struct tftphdr *tp, int size)
                 exit(0);
             }
             if (verbosity >= 1) {
+                tmp_p = (char *)inet_ntop(from.sa.sa_family, SOCKADDR_P(&from),
+                                          tmpbuf, INET6_ADDRSTRLEN);
+                if (!tmp_p) {
+                    tmp_p = tmpbuf;
+                    strcpy(tmpbuf, "???");
+                }
                 if (filename == origfilename
                     || !strcmp(filename, origfilename))
                     syslog(LOG_NOTICE, "%s from %s filename %s\n",
                            tp_opcode == WRQ ? "WRQ" : "RRQ",
-                           inet_ntoa(from.sin_addr), filename);
+                           tmp_p, filename);
                 else
                     syslog(LOG_NOTICE,
                            "%s from %s filename %s remapped to %s\n",
                            tp_opcode == WRQ ? "WRQ" : "RRQ",
-                           inet_ntoa(from.sin_addr), origfilename,
+                           tmp_p, origfilename,
                            filename);
             }
             ecode =
@@ -998,20 +1166,41 @@ int rewrite_macros(char macro, char *output);
 
 int rewrite_macros(char macro, char *output)
 {
-    char *p;
+    char *p, tb[INET6_ADDRSTRLEN];
+    int l=0;
 
     switch (macro) {
     case 'i':
-        p = inet_ntoa(from.sin_addr);
-        if (output)
+        p = (char *)inet_ntop(from.sa.sa_family, SOCKADDR_P(&from),
+                              tb, INET6_ADDRSTRLEN);
+        if (output && p)
             strcpy(output, p);
-        return strlen(p);
+        if (!p)
+            return 0;
+        else
+            return strlen(p);
 
     case 'x':
-        if (output)
-            sprintf(output, "%08lX",
-                    (unsigned long)ntohl(from.sin_addr.s_addr));
-        return 8;
+        if (output) {
+            if (from.sa.sa_family == AF_INET) {
+                sprintf(output, "%08lX",
+                    (unsigned long)ntohl(from.si.sin_addr.s_addr));
+                l = 8;
+#ifdef HAVE_IPV6
+            } else {
+                unsigned char *c = (unsigned char *)SOCKADDR_P(&from);
+                p = tb;
+                for (l = 0; l < 16; l++) {
+                    sprintf(p, "%02X", *c);
+                    c++;
+                    p += 2;
+                }
+                strcpy(output, tb);
+                l = strlen(tb);
+#endif
+            }
+        }
+        return l;
 
     default:
         return -1;
@@ -1398,8 +1587,14 @@ static void nak(int error, const char *msg)
     length += 4;                /* Add space for header */
 
     if (verbosity >= 2) {
+        tmp_p = (char *)inet_ntop(from.sa.sa_family, SOCKADDR_P(&from),
+                                  tmpbuf, INET6_ADDRSTRLEN);
+        if (!tmp_p) {
+            tmp_p = tmpbuf;
+            strcpy(tmpbuf, "???");
+        }
         syslog(LOG_INFO, "sending NAK (%d, %s) to %s",
-               error, tp->th_msg, inet_ntoa(from.sin_addr));
+               error, tp->th_msg, tmp_p);
     }
 
     if (send(peer, buf, length, 0) != length)