2 files changed, 82 insertions, 0 deletions

diff --git a/tftp.c b/tftp.c
index c13ca15..95ab9d5 100644
--- a/tftp.c
+++ b/tftp.c
@@ -121,6 +121,43 @@ static int tftp_read_data(struct tftp_session *spt, u_int16_t block_nr,
     return bytes_read;
 }
 
+static int tftp_send_oack(struct tftp_session *spt, const char *key,
+                          uint32_t value, struct tftp_t *recv_tp)
+{
+    struct sockaddr_in saddr, daddr;
+    struct mbuf *m;
+    struct tftp_t *tp;
+    int n = 0;
+
+    m = m_get();
+
+    if (!m)
+        return -1;
+
+    memset(m->m_data, 0, m->m_size);
+
+    m->m_data += if_maxlinkhdr;
+    tp = (void *)m->m_data;
+    m->m_data += sizeof(struct udpiphdr);
+
+    tp->tp_op = htons(TFTP_OACK);
+    n += sprintf(tp->x.tp_buf + n, "%s", key) + 1;
+    n += sprintf(tp->x.tp_buf + n, "%u", value) + 1;
+
+    saddr.sin_addr = recv_tp->ip.ip_dst;
+    saddr.sin_port = recv_tp->udp.uh_dport;
+
+    daddr.sin_addr = spt->client_ip;
+    daddr.sin_port = spt->client_port;
+
+    m->m_len = sizeof(struct tftp_t) - 514 + n - sizeof(struct ip) -
+               sizeof(struct udphdr);
+    udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
+
+    return 0;
+}
+
+
 static int tftp_send_error(struct tftp_session *spt, u_int16_t errorcode,
                            const char *msg, struct tftp_t *recv_tp)
 {
@@ -270,6 +307,8 @@ static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
         return;
     }
 
+    k += 6; /* skipping octet */
+
     /* do sanity checks on the filename */
 
     if ((spt->filename[0] != '/') ||
@@ -294,6 +333,48 @@ static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
         return;
     }
 
+    if (src[n - 1] != 0) {
+        tftp_send_error(spt, 2, "Access violation", tp);
+        return;
+    }
+
+    while (k < n) {
+        const char *key, *value;
+
+        key = src + k;
+        k += strlen(key) + 1;
+
+        if (k >= n) {
+            tftp_send_error(spt, 2, "Access violation", tp);
+            return;
+        }
+
+        value = src + k;
+        k += strlen(value) + 1;
+
+        if (strcmp(key, "tsize") == 0) {
+            int tsize = atoi(value);
+            struct stat stat_p;
+
+            if (tsize == 0 && tftp_prefix) {
+                char buffer[1024];
+                int len;
+
+                len = snprintf(buffer, sizeof(buffer), "%s/%s", tftp_prefix,
+                               spt->filename);
+
+                if (stat(buffer, &stat_p) == 0)
+                    tsize = stat_p.st_size;
+                else {
+                    tftp_send_error(spt, 1, "File not found", tp);
+                    return;
+                }
+            }
+
+            tftp_send_oack(spt, "tsize", tsize, tp);
+        }
+    }
+
     tftp_send_data(spt, 1, tp);
 }
 
diff --git a/tftp.h b/tftp.h
index 4d0996d..039bb87 100644
--- a/tftp.h
+++ b/tftp.h
@@ -9,6 +9,7 @@
 #define TFTP_DATA 3
 #define TFTP_ACK 4
 #define TFTP_ERROR 5
+#define TFTP_OACK 6
 
 #define TFTP_FILENAME_MAX 512