Imported Upstream version 1.3.0upstream/1.3.0

16 files changed, 414 insertions, 71 deletions

diff --git a/slirp/Makefile.objs b/slirp/Makefile.objs
index bb43d3c08..2daa9dc58 100644
--- a/slirp/Makefile.objs
+++ b/slirp/Makefile.objs
@@ -1,3 +1,3 @@
-common-obj-y = cksum.o if.o ip_icmp.o ip_input.o ip_output.o
+common-obj-y = cksum.o if.o ip_icmp.o ip_input.o ip_output.o dnssearch.o
 common-obj-y += slirp.o mbuf.o misc.o sbuf.o socket.o tcp_input.o tcp_output.o
 common-obj-y += tcp_subr.o tcp_timer.o udp.o bootp.o tftp.o arp_table.o
diff --git a/slirp/arp_table.c b/slirp/arp_table.c
index 5d7b8acd1..bf698c1ac 100644
--- a/slirp/arp_table.c
+++ b/slirp/arp_table.c
@@ -38,7 +38,9 @@ void arp_table_add(Slirp *slirp, uint32_t ip_addr, uint8_t ethaddr[ETH_ALEN])
                 ethaddr[3], ethaddr[4], ethaddr[5]));
 
     /* Check 0.0.0.0/8 invalid source-only addresses */
-    assert((ip_addr & htonl(~(0xf << 28))) != 0);
+    if ((ip_addr & htonl(~(0xf << 28))) == 0) {
+        return;
+    }
 
     if (ip_addr == 0xffffffff || ip_addr == broadcast_addr) {
         /* Do not register broadcast addresses */
diff --git a/slirp/bootp.c b/slirp/bootp.c
index 64eac7d10..b7db9fa33 100644
--- a/slirp/bootp.c
+++ b/slirp/bootp.c
@@ -287,6 +287,18 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp)
             memcpy(q, slirp->client_hostname, val);
             q += val;
         }
+
+        if (slirp->vdnssearch) {
+            size_t spaceleft = sizeof(rbp->bp_vend) - (q - rbp->bp_vend);
+            val = slirp->vdnssearch_len;
+            if (val + 1 > spaceleft) {
+                g_warning("DHCP packet size exceeded, "
+                    "omitting domain-search option.");
+            } else {
+                memcpy(q, slirp->vdnssearch, val);
+                q += val;
+            }
+        }
     } else {
         static const char nak_msg[] = "requested address not available";
 
diff --git a/slirp/dnssearch.c b/slirp/dnssearch.c
new file mode 100644
index 000000000..4c9064ecb
--- /dev/null
+++ b/slirp/dnssearch.c
@@ -0,0 +1,314 @@
+/*
+ * Domain search option for DHCP (RFC 3397)
+ *
+ * Copyright (c) 2012 Klaus Stengel
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <glib.h>
+#include "slirp.h"
+
+static const uint8_t RFC3397_OPT_DOMAIN_SEARCH = 119;
+static const uint8_t MAX_OPT_LEN = 255;
+static const uint8_t OPT_HEADER_LEN = 2;
+static const uint8_t REFERENCE_LEN = 2;
+
+struct compact_domain;
+
+typedef struct compact_domain {
+    struct compact_domain *self;
+    struct compact_domain *refdom;
+    uint8_t *labels;
+    size_t len;
+    size_t common_octets;
+} CompactDomain;
+
+static size_t
+domain_suffix_diffoff(const CompactDomain *a, const CompactDomain *b)
+{
+    size_t la = a->len, lb = b->len;
+    uint8_t *da = a->labels + la, *db = b->labels + lb;
+    size_t i, lm = (la < lb) ? la : lb;
+
+    for (i = 0; i < lm; i++) {
+        da--; db--;
+        if (*da != *db) {
+            break;
+        }
+    }
+    return i;
+}
+
+static int domain_suffix_ord(const void *cva, const void *cvb)
+{
+    const CompactDomain *a = cva, *b = cvb;
+    size_t la = a->len, lb = b->len;
+    size_t doff = domain_suffix_diffoff(a, b);
+    uint8_t ca = a->labels[la - doff];
+    uint8_t cb = b->labels[lb - doff];
+
+    if (ca < cb) {
+        return -1;
+    }
+    if (ca > cb) {
+        return 1;
+    }
+    if (la < lb) {
+        return -1;
+    }
+    if (la > lb) {
+        return 1;
+    }
+    return 0;
+}
+
+static size_t domain_common_label(CompactDomain *a, CompactDomain *b)
+{
+    size_t res, doff = domain_suffix_diffoff(a, b);
+    uint8_t *first_eq_pos = a->labels + (a->len - doff);
+    uint8_t *label = a->labels;
+
+    while (*label && label < first_eq_pos) {
+        label += *label + 1;
+    }
+    res = a->len - (label - a->labels);
+    /* only report if it can help to reduce the packet size */
+    return (res > REFERENCE_LEN) ? res : 0;
+}
+
+static void domain_fixup_order(CompactDomain *cd, size_t n)
+{
+    size_t i;
+
+    for (i = 0; i < n; i++) {
+        CompactDomain *cur = cd + i, *next = cd[i].self;
+
+        while (!cur->common_octets) {
+            CompactDomain *tmp = next->self; /* backup target value */
+
+            next->self = cur;
+            cur->common_octets++;
+
+            cur = next;
+            next = tmp;
+        }
+    }
+}
+
+static void domain_mklabels(CompactDomain *cd, const char *input)
+{
+    uint8_t *len_marker = cd->labels;
+    uint8_t *output = len_marker; /* pre-incremented */
+    const char *in = input;
+    char cur_chr;
+    size_t len = 0;
+
+    if (cd->len == 0) {
+        goto fail;
+    }
+    cd->len++;
+
+    do {
+        cur_chr = *in++;
+        if (cur_chr == '.' || cur_chr == '\0') {
+            len = output - len_marker;
+            if ((len == 0 && cur_chr == '.') || len >= 64) {
+                goto fail;
+            }
+            *len_marker = len;
+
+            output++;
+            len_marker = output;
+        } else {
+            output++;
+            *output = cur_chr;
+        }
+    } while (cur_chr != '\0');
+
+    /* ensure proper zero-termination */
+    if (len != 0) {
+        *len_marker = 0;
+        cd->len++;
+    }
+    return;
+
+fail:
+    g_warning("failed to parse domain name '%s'\n", input);
+    cd->len = 0;
+}
+
+static void
+domain_mkxrefs(CompactDomain *doms, CompactDomain *last, size_t depth)
+{
+    CompactDomain *i = doms, *target = doms;
+
+    do {
+        if (i->labels < target->labels) {
+            target = i;
+        }
+    } while (i++ != last);
+
+    for (i = doms; i != last; i++) {
+        CompactDomain *group_last;
+        size_t next_depth;
+
+        if (i->common_octets == depth) {
+            continue;
+        }
+
+        next_depth = -1;
+        for (group_last = i; group_last != last; group_last++) {
+            size_t co = group_last->common_octets;
+            if (co <= depth) {
+                break;
+            }
+            if (co < next_depth) {
+                next_depth = co;
+            }
+        }
+        domain_mkxrefs(i, group_last, next_depth);
+
+        i = group_last;
+        if (i == last) {
+            break;
+        }
+    }
+
+    if (depth == 0) {
+        return;
+    }
+
+    i = doms;
+    do {
+        if (i != target && i->refdom == NULL) {
+            i->refdom = target;
+            i->common_octets = depth;
+        }
+    } while (i++ != last);
+}
+
+static size_t domain_compactify(CompactDomain *domains, size_t n)
+{
+    uint8_t *start = domains->self->labels, *outptr = start;
+    size_t i;
+
+    for (i = 0; i < n; i++) {
+        CompactDomain *cd = domains[i].self;
+        CompactDomain *rd = cd->refdom;
+
+        if (rd != NULL) {
+            size_t moff = (rd->labels - start)
+                    + (rd->len - cd->common_octets);
+            if (moff < 0x3FFFu) {
+                cd->len -= cd->common_octets - 2;
+                cd->labels[cd->len - 1] = moff & 0xFFu;
+                cd->labels[cd->len - 2] = 0xC0u | (moff >> 8);
+            }
+        }
+
+        if (cd->labels != outptr) {
+            memmove(outptr, cd->labels, cd->len);
+            cd->labels = outptr;
+        }
+        outptr += cd->len;
+    }
+    return outptr - start;
+}
+
+int translate_dnssearch(Slirp *s, const char **names)
+{
+    size_t blocks, bsrc_start, bsrc_end, bdst_start;
+    size_t i, num_domains, memreq = 0;
+    uint8_t *result = NULL, *outptr;
+    CompactDomain *domains = NULL;
+    const char **nameptr = names;
+
+    while (*nameptr != NULL) {
+        nameptr++;
+    }
+
+    num_domains = nameptr - names;
+    if (num_domains == 0) {
+        return -2;
+    }
+
+    domains = g_malloc(num_domains * sizeof(*domains));
+
+    for (i = 0; i < num_domains; i++) {
+        size_t nlen = strlen(names[i]);
+        memreq += nlen + 2; /* 1 zero octet + 1 label length octet */
+        domains[i].self = domains + i;
+        domains[i].len = nlen;
+        domains[i].common_octets = 0;
+        domains[i].refdom = NULL;
+    }
+
+    /* reserve extra 2 header bytes for each 255 bytes of output */
+    memreq += ((memreq + MAX_OPT_LEN - 1) / MAX_OPT_LEN) * OPT_HEADER_LEN;
+    result = g_malloc(memreq * sizeof(*result));
+
+    outptr = result;
+    for (i = 0; i < num_domains; i++) {
+        domains[i].labels = outptr;
+        domain_mklabels(domains + i, names[i]);
+        outptr += domains[i].len;
+    }
+
+    if (outptr == result) {
+        g_free(domains);
+        g_free(result);
+        return -1;
+    }
+
+    qsort(domains, num_domains, sizeof(*domains), domain_suffix_ord);
+    domain_fixup_order(domains, num_domains);
+
+    for (i = 1; i < num_domains; i++) {
+        size_t cl = domain_common_label(domains + i - 1, domains + i);
+        domains[i - 1].common_octets = cl;
+    }
+
+    domain_mkxrefs(domains, domains + num_domains - 1, 0);
+    memreq = domain_compactify(domains, num_domains);
+
+    blocks = (memreq + MAX_OPT_LEN - 1) / MAX_OPT_LEN;
+    bsrc_end = memreq;
+    bsrc_start = (blocks - 1) * MAX_OPT_LEN;
+    bdst_start = bsrc_start + blocks * OPT_HEADER_LEN;
+    memreq += blocks * OPT_HEADER_LEN;
+
+    while (blocks--) {
+        size_t len = bsrc_end - bsrc_start;
+        memmove(result + bdst_start, result + bsrc_start, len);
+        result[bdst_start - 2] = RFC3397_OPT_DOMAIN_SEARCH;
+        result[bdst_start - 1] = len;
+        bsrc_end = bsrc_start;
+        bsrc_start -= MAX_OPT_LEN;
+        bdst_start -= MAX_OPT_LEN + OPT_HEADER_LEN;
+    }
+
+    g_free(domains);
+    s->vdnssearch = result;
+    s->vdnssearch_len = memreq;
+    return 0;
+}
diff --git a/slirp/ip_icmp.h b/slirp/ip_icmp.h
index 1a1af91e1..be4426b8e 100644
--- a/slirp/ip_icmp.h
+++ b/slirp/ip_icmp.h
@@ -92,8 +92,8 @@ struct icmp {
 
 /*
  * Lower bounds on packet lengths for various types.
- * For the error advice packets must first insure that the
- * packet is large enought to contain the returned ip header.
+ * For the error advice packets must first ensure that the
+ * packet is large enough to contain the returned ip header.
  * Only then can we do the check to see if 64 bits of packet
  * data have been returned, since we need to check the returned
  * ip header length.
diff --git a/slirp/ip_input.c b/slirp/ip_input.c
index ce24faf16..6f4cff8fd 100644
--- a/slirp/ip_input.c
+++ b/slirp/ip_input.c
@@ -213,7 +213,6 @@ ip_input(struct mbuf *m)
 	return;
 bad:
 	m_free(m);
-	return;
 }
 
 #define iptofrag(P) ((struct ipasfrag *)(((char*)(P)) - sizeof(struct qlink)))
diff --git a/slirp/libslirp.h b/slirp/libslirp.h
index 9b471b505..49609c2ad 100644
--- a/slirp/libslirp.h
+++ b/slirp/libslirp.h
@@ -12,7 +12,8 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
                   struct in_addr vnetmask, struct in_addr vhost,
                   const char *vhostname, const char *tftp_path,
                   const char *bootfile, struct in_addr vdhcp_start,
-                  struct in_addr vnameserver, void *opaque);
+                  struct in_addr vnameserver, const char **vdnssearch,
+                  void *opaque);
 void slirp_cleanup(Slirp *slirp);
 
 void slirp_update_timeout(uint32_t *timeout);
diff --git a/slirp/misc.c b/slirp/misc.c
index 0bee86433..664532a66 100644
--- a/slirp/misc.c
+++ b/slirp/misc.c
@@ -253,20 +253,6 @@ void lprint(const char *format, ...)
     va_end(args);
 }
 
-void
-u_sleep(int usec)
-{
-	struct timeval t;
-	fd_set fdset;
-
-	FD_ZERO(&fdset);
-
-	t.tv_sec = 0;
-	t.tv_usec = usec * 1000;
-
-	select(0, &fdset, &fdset, &fdset, &t);
-}
-
 void slirp_connection_info(Slirp *slirp, Monitor *mon)
 {
     const char * const tcpstates[] = {
diff --git a/slirp/misc.h b/slirp/misc.h
index ed40a103c..cc36aeb95 100644
--- a/slirp/misc.h
+++ b/slirp/misc.h
@@ -64,7 +64,6 @@ void snooze_hup(int);
 void snooze(void);
 void relay(int);
 void add_emu(char *);
-void u_sleep(int);
 void fd_nonblock(int);
 void fd_block(int);
 int rsh_exec(struct socket *, struct socket *, char *, char *, char *);
diff --git a/slirp/slirp.c b/slirp/slirp.c
index 38e0a2193..3395d509a 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -203,7 +203,8 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
                   struct in_addr vnetmask, struct in_addr vhost,
                   const char *vhostname, const char *tftp_path,
                   const char *bootfile, struct in_addr vdhcp_start,
-                  struct in_addr vnameserver, void *opaque)
+                  struct in_addr vnameserver, const char **vdnssearch,
+                  void *opaque)
 {
     Slirp *slirp = g_malloc0(sizeof(Slirp));
 
@@ -233,6 +234,10 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
     slirp->vdhcp_startaddr = vdhcp_start;
     slirp->vnameserver_addr = vnameserver;
 
+    if (vdnssearch) {
+        translate_dnssearch(slirp, vdnssearch);
+    }
+
     slirp->opaque = opaque;
 
     register_savevm(NULL, "slirp", 0, 3,
@@ -252,6 +257,7 @@ void slirp_cleanup(Slirp *slirp)
     ip_cleanup(slirp);
     m_cleanup(slirp);
 
+    g_free(slirp->vdnssearch);
     g_free(slirp->tftp_prefix);
     g_free(slirp->bootp_filename);
     g_free(slirp);
diff --git a/slirp/slirp.h b/slirp/slirp.h
index f2c5eca89..0107b07e6 100644
--- a/slirp/slirp.h
+++ b/slirp/slirp.h
@@ -235,6 +235,8 @@ struct Slirp {
     /* bootp/dhcp states */
     BOOTPClient bootp_clients[NB_BOOTP_CLIENTS];
     char *bootp_filename;
+    size_t vdnssearch_len;
+    uint8_t *vdnssearch;
 
     /* tcp states */
     struct socket tcb;
@@ -294,6 +296,9 @@ void lprint(const char *, ...) GCC_FMT_ATTR(1, 2);
 #define SO_OPTIONS DO_KEEPALIVE
 #define TCP_MAXIDLE (TCPTV_KEEPCNT * TCPTV_KEEPINTVL)
 
+/* dnssearch.c */
+int translate_dnssearch(Slirp *s, const char ** names);
+
 /* cksum.c */
 int cksum(struct mbuf *m, int len);
 
diff --git a/slirp/tcp_input.c b/slirp/tcp_input.c
index 942aaf44f..6440eae7f 100644
--- a/slirp/tcp_input.c
+++ b/slirp/tcp_input.c
@@ -1281,8 +1281,6 @@ drop:
 	 * Drop space held by incoming segment and return.
 	 */
 	m_free(m);
-
-	return;
 }
 
 static void
diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c
index 025b37436..1542e4361 100644
--- a/slirp/tcp_subr.c
+++ b/slirp/tcp_subr.c
@@ -114,9 +114,9 @@ tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
 	int win = 0;
 
 	DEBUG_CALL("tcp_respond");
-	DEBUG_ARG("tp = %lx", (long)tp);
-	DEBUG_ARG("ti = %lx", (long)ti);
-	DEBUG_ARG("m = %lx", (long)m);
+	DEBUG_ARG("tp = %p", tp);
+	DEBUG_ARG("ti = %p", ti);
+	DEBUG_ARG("m = %p", m);
 	DEBUG_ARG("ack = %u", ack);
 	DEBUG_ARG("seq = %u", seq);
 	DEBUG_ARG("flags = %x", flags);
@@ -124,7 +124,7 @@ tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
 	if (tp)
 		win = sbspace(&tp->t_socket->so_rcv);
         if (m == NULL) {
-		if ((m = m_get(tp->t_socket->slirp)) == NULL)
+		if (!tp || (m = m_get(tp->t_socket->slirp)) == NULL)
 			return;
 		tlen = 0;
 		m->m_data += IF_MAXLINKHDR;
diff --git a/slirp/tftp.c b/slirp/tftp.c
index b78765f3a..1a79c45cf 100644
--- a/slirp/tftp.c
+++ b/slirp/tftp.c
@@ -37,6 +37,10 @@ static inline void tftp_session_update(struct tftp_session *spt)
 
 static void tftp_session_terminate(struct tftp_session *spt)
 {
+    if (spt->fd >= 0) {
+        close(spt->fd);
+        spt->fd = -1;
+    }
     g_free(spt->filename);
     spt->slirp = NULL;
 }
@@ -54,7 +58,7 @@ static int tftp_session_allocate(Slirp *slirp, struct tftp_t *tp)
 
     /* sessions time out after 5 inactive seconds */
     if ((int)(curtime - spt->timestamp) > 5000) {
-        g_free(spt->filename);
+        tftp_session_terminate(spt);
         goto found;
     }
   }
@@ -64,6 +68,7 @@ static int tftp_session_allocate(Slirp *slirp, struct tftp_t *tp)
  found:
   memset(spt, 0, sizeof(*spt));
   memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
+  spt->fd = -1;
   spt->client_port = tp->udp.uh_sport;
   spt->slirp = slirp;
 
@@ -92,37 +97,36 @@ static int tftp_session_find(Slirp *slirp, struct tftp_t *tp)
   return -1;
 }
 
-static int tftp_read_data(struct tftp_session *spt, uint16_t block_nr,
+static int tftp_read_data(struct tftp_session *spt, uint32_t block_nr,
                           uint8_t *buf, int len)
 {
-  int fd;
-  int bytes_read = 0;
+    int bytes_read = 0;
 
-  fd = open(spt->filename, O_RDONLY | O_BINARY);
+    if (spt->fd < 0) {
+        spt->fd = open(spt->filename, O_RDONLY | O_BINARY);
+    }
 
-  if (fd < 0) {
-    return -1;
-  }
+    if (spt->fd < 0) {
+        return -1;
+    }
 
-  if (len) {
-    lseek(fd, block_nr * 512, SEEK_SET);
+    if (len) {
+        lseek(spt->fd, block_nr * 512, SEEK_SET);
 
-    bytes_read = read(fd, buf, len);
-  }
-
-  close(fd);
+        bytes_read = read(spt->fd, buf, len);
+    }
 
-  return bytes_read;
+    return bytes_read;
 }
 
 static int tftp_send_oack(struct tftp_session *spt,
-                          const char *key, uint32_t value,
+                          const char *keys[], uint32_t values[], int nb,
                           struct tftp_t *recv_tp)
 {
     struct sockaddr_in saddr, daddr;
     struct mbuf *m;
     struct tftp_t *tp;
-    int n = 0;
+    int i, n = 0;
 
     m = m_get(spt->slirp);
 
@@ -136,10 +140,12 @@ static int tftp_send_oack(struct tftp_session *spt,
     m->m_data += sizeof(struct udpiphdr);
 
     tp->tp_op = htons(TFTP_OACK);
-    n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
-                  key) + 1;
-    n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
-                  value) + 1;
+    for (i = 0; i < nb; i++) {
+        n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
+                      keys[i]) + 1;
+        n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
+                      values[i]) + 1;
+    }
 
     saddr.sin_addr = recv_tp->ip.ip_dst;
     saddr.sin_port = recv_tp->udp.uh_dport;
@@ -193,23 +199,18 @@ out:
   tftp_session_terminate(spt);
 }
 
-static int tftp_send_data(struct tftp_session *spt,
-                          uint16_t block_nr,
-			  struct tftp_t *recv_tp)
+static void tftp_send_next_block(struct tftp_session *spt,
+                                 struct tftp_t *recv_tp)
 {
   struct sockaddr_in saddr, daddr;
   struct mbuf *m;
   struct tftp_t *tp;
   int nobytes;
 
-  if (block_nr < 1) {
-    return -1;
-  }
-
   m = m_get(spt->slirp);
 
   if (!m) {
-    return -1;
+    return;
   }
 
   memset(m->m_data, 0, m->m_size);
@@ -219,7 +220,7 @@ static int tftp_send_data(struct tftp_session *spt,
   m->m_data += sizeof(struct udpiphdr);
 
   tp->tp_op = htons(TFTP_DATA);
-  tp->x.tp_data.tp_block_nr = htons(block_nr);
+  tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff);
 
   saddr.sin_addr = recv_tp->ip.ip_dst;
   saddr.sin_port = recv_tp->udp.uh_dport;
@@ -227,7 +228,7 @@ static int tftp_send_data(struct tftp_session *spt,
   daddr.sin_addr = spt->client_ip;
   daddr.sin_port = spt->client_port;
 
-  nobytes = tftp_read_data(spt, block_nr - 1, tp->x.tp_data.tp_buf, 512);
+  nobytes = tftp_read_data(spt, spt->block_nr, tp->x.tp_data.tp_buf, 512);
 
   if (nobytes < 0) {
     m_free(m);
@@ -236,7 +237,7 @@ static int tftp_send_data(struct tftp_session *spt,
 
     tftp_send_error(spt, 1, "File not found", tp);
 
-    return -1;
+    return;
   }
 
   m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
@@ -251,7 +252,7 @@ static int tftp_send_data(struct tftp_session *spt,
     tftp_session_terminate(spt);
   }
 
-  return 0;
+  spt->block_nr++;
 }
 
 static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
@@ -260,6 +261,9 @@ static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
   int s, k;
   size_t prefix_len;
   char *req_fname;
+  const char *option_name[2];
+  uint32_t option_value[2];
+  int nb_options = 0;
 
   /* check if a session already exists and if so terminate it */
   s = tftp_session_find(slirp, tp);
@@ -337,7 +341,7 @@ static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
       return;
   }
 
-  while (k < pktlen) {
+  while (k < pktlen && nb_options < ARRAY_SIZE(option_name)) {
       const char *key, *value;
 
       key = &tp->x.tp_buf[k];
@@ -364,12 +368,32 @@ static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
 	      }
 	  }
 
-	  tftp_send_oack(spt, "tsize", tsize, tp);
-	  return;
+          option_name[nb_options] = "tsize";
+          option_value[nb_options] = tsize;
+          nb_options++;
+      } else if (strcasecmp(key, "blksize") == 0) {
+          int blksize = atoi(value);
+
+          /* If blksize option is bigger than what we will
+           * emit, accept the option with our packet size.
+           * Otherwise, simply do as we didn't see the option.
+           */
+          if (blksize >= 512) {
+              option_name[nb_options] = "blksize";
+              option_value[nb_options] = 512;
+              nb_options++;
+          }
       }
   }
 
-  tftp_send_data(spt, 1, tp);
+  if (nb_options > 0) {
+      assert(nb_options <= ARRAY_SIZE(option_name));
+      tftp_send_oack(spt, option_name, option_value, nb_options, tp);
+      return;
+  }
+
+  spt->block_nr = 0;
+  tftp_send_next_block(spt, tp);
 }
 
 static void tftp_handle_ack(Slirp *slirp, struct tftp_t *tp, int pktlen)
@@ -382,11 +406,7 @@ static void tftp_handle_ack(Slirp *slirp, struct tftp_t *tp, int pktlen)
     return;
   }
 
-  if (tftp_send_data(&slirp->tftp_sessions[s],
-		     ntohs(tp->x.tp_data.tp_block_nr) + 1,
-		     tp) < 0) {
-    return;
-  }
+  tftp_send_next_block(&slirp->tftp_sessions[s], tp);
 }
 
 static void tftp_handle_error(Slirp *slirp, struct tftp_t *tp, int pktlen)
diff --git a/slirp/tftp.h b/slirp/tftp.h
index 72e5e91be..51704e487 100644
--- a/slirp/tftp.h
+++ b/slirp/tftp.h
@@ -33,9 +33,11 @@ struct tftp_t {
 struct tftp_session {
     Slirp *slirp;
     char *filename;
+    int fd;
 
     struct in_addr client_ip;
     uint16_t client_port;
+    uint32_t block_nr;
 
     int timestamp;
 };
diff --git a/slirp/udp.c b/slirp/udp.c
index ced509656..9286cb7d3 100644
--- a/slirp/udp.c
+++ b/slirp/udp.c
@@ -231,7 +231,6 @@ udp_input(register struct mbuf *m, int iphlen)
 	return;
 bad:
 	m_free(m);
-	return;
 }
 
 int udp_output2(struct socket *so, struct mbuf *m,