New upstream version 2.4.0upstream/2.4.0

1 files changed, 169 insertions, 152 deletions

diff --git a/src/openvpn/dhcp.c b/src/openvpn/dhcp.c
index 8d0b18a..c17a22e 100644
--- a/src/openvpn/dhcp.c
+++ b/src/openvpn/dhcp.c
@@ -5,7 +5,7 @@
  *             packet encryption, packet authentication, and
  *             packet compression.
  *
- *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
+ *  Copyright (C) 2002-2017 OpenVPN Technologies, Inc. <sales@openvpn.net>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2
@@ -37,176 +37,193 @@
 #include "memdbg.h"
 
 static int
-get_dhcp_message_type (const struct dhcp *dhcp, const int optlen)
+get_dhcp_message_type(const struct dhcp *dhcp, const int optlen)
 {
-  const uint8_t *p = (uint8_t *) (dhcp + 1);
-  int i;
+    const uint8_t *p = (uint8_t *) (dhcp + 1);
+    int i;
 
-  for (i = 0; i < optlen; ++i)
+    for (i = 0; i < optlen; ++i)
     {
-      const uint8_t type = p[i];
-      const int room = optlen - i;
-      if (type == DHCP_END)           /* didn't find what we were looking for */
-	return -1;
-      else if (type == DHCP_PAD)      /* no-operation */
-	;
-      else if (type == DHCP_MSG_TYPE) /* what we are looking for */
-	{
-	  if (room >= 3)
-	    {
-	      if (p[i+1] == 1)        /* option length should be 1 */
-		return p[i+2];        /* return message type */
-	    }
-	  return -1;
-	}
-      else                            /* some other option */
-	{
-	  if (room >= 2)
-	    {
-	      const int len = p[i+1]; /* get option length */
-	      i += (len + 1);         /* advance to next option */
-	    }
-	}
+        const uint8_t type = p[i];
+        const int room = optlen - i;
+        if (type == DHCP_END)         /* didn't find what we were looking for */
+        {
+            return -1;
+        }
+        else if (type == DHCP_PAD)    /* no-operation */
+        {
+        }
+        else if (type == DHCP_MSG_TYPE) /* what we are looking for */
+        {
+            if (room >= 3)
+            {
+                if (p[i+1] == 1)      /* option length should be 1 */
+                {
+                    return p[i+2];    /* return message type */
+                }
+            }
+            return -1;
+        }
+        else                          /* some other option */
+        {
+            if (room >= 2)
+            {
+                const int len = p[i+1]; /* get option length */
+                i += (len + 1);       /* advance to next option */
+            }
+        }
     }
-  return -1;
+    return -1;
 }
 
 static in_addr_t
-do_extract (struct dhcp *dhcp, int optlen)
+do_extract(struct dhcp *dhcp, int optlen)
 {
-  uint8_t *p = (uint8_t *) (dhcp + 1);
-  int i;
-  in_addr_t ret = 0;
+    uint8_t *p = (uint8_t *) (dhcp + 1);
+    int i;
+    in_addr_t ret = 0;
 
-  for (i = 0; i < optlen; )
+    for (i = 0; i < optlen; )
     {
-      const uint8_t type = p[i];
-      const int room = optlen - i;
-      if (type == DHCP_END)
-	break;
-      else if (type == DHCP_PAD)
-	++i;
-      else if (type == DHCP_ROUTER)
-	{
-	  if (room >= 2)
-	    {
-	      const int len = p[i+1]; /* get option length */
-	      if (len <= (room-2))
-		{
-		  /* get router IP address */
-		  if (!ret && len >= 4 && (len & 3) == 0)
-		    {
-		      memcpy (&ret, p+i+2, 4);
-		      ret = ntohl (ret);
-		    }
-		  {
-		    /* delete the router option */
-		    uint8_t *dest = p + i;
-		    const int owlen = len + 2;            /* len of data to overwrite */
-		    uint8_t *src = dest + owlen;
-		    uint8_t *end = p + optlen;
-		    const int movlen = end - src;
-		    if (movlen > 0)
-		      memmove(dest, src, movlen);         /* overwrite router option */
-		    memset(end - owlen, DHCP_PAD, owlen); /* pad tail */		    
-		  }
-		}
-	      else
-		break;
-	    }
-	  else
-	    break;
-	}
-      else                              /* some other option */
-	{
-	  if (room >= 2)
-	    {
-	      const int len = p[i+1];   /* get option length */
-	      i += (len + 2);           /* advance to next option */
-	    }
-	  else
-	    break;
-	}
+        const uint8_t type = p[i];
+        const int room = optlen - i;
+        if (type == DHCP_END)
+        {
+            break;
+        }
+        else if (type == DHCP_PAD)
+        {
+            ++i;
+        }
+        else if (type == DHCP_ROUTER)
+        {
+            if (room >= 2)
+            {
+                const int len = p[i+1]; /* get option length */
+                if (len <= (room-2))
+                {
+                    /* get router IP address */
+                    if (!ret && len >= 4 && (len & 3) == 0)
+                    {
+                        memcpy(&ret, p+i+2, 4);
+                        ret = ntohl(ret);
+                    }
+                    {
+                        /* delete the router option */
+                        uint8_t *dest = p + i;
+                        const int owlen = len + 2;        /* len of data to overwrite */
+                        uint8_t *src = dest + owlen;
+                        uint8_t *end = p + optlen;
+                        const int movlen = end - src;
+                        if (movlen > 0)
+                        {
+                            memmove(dest, src, movlen);   /* overwrite router option */
+                        }
+                        memset(end - owlen, DHCP_PAD, owlen); /* pad tail */
+                    }
+                }
+                else
+                {
+                    break;
+                }
+            }
+            else
+            {
+                break;
+            }
+        }
+        else                            /* some other option */
+        {
+            if (room >= 2)
+            {
+                const int len = p[i+1]; /* get option length */
+                i += (len + 2);         /* advance to next option */
+            }
+            else
+            {
+                break;
+            }
+        }
     }
-  return ret;
+    return ret;
 }
 
 static uint16_t
-udp_checksum (const uint8_t *buf,
-	      const int len_udp,
-	      const uint8_t *src_addr,
-	      const uint8_t *dest_addr)
+udp_checksum(const uint8_t *buf,
+             const int len_udp,
+             const uint8_t *src_addr,
+             const uint8_t *dest_addr)
 {
-  uint16_t word16;
-  uint32_t sum = 0;
-  int i;
-	
-  /* make 16 bit words out of every two adjacent 8 bit words and  */
-  /* calculate the sum of all 16 bit words */
-  for (i = 0; i < len_udp; i += 2){
-    word16 = ((buf[i] << 8) & 0xFF00) + ((i + 1 < len_udp) ? (buf[i+1] & 0xFF) : 0);
-    sum += word16;
-  }
-
-  /* add the UDP pseudo header which contains the IP source and destination addresses */
-  for (i = 0; i < 4; i += 2){
-    word16 =((src_addr[i] << 8) & 0xFF00) + (src_addr[i+1] & 0xFF);
-    sum += word16;
-  }
-  for (i = 0; i < 4; i += 2){
-    word16 =((dest_addr[i] << 8) & 0xFF00) + (dest_addr[i+1] & 0xFF);
-    sum += word16; 	
-  }
-
-  /* the protocol number and the length of the UDP packet */
-  sum += (uint16_t) OPENVPN_IPPROTO_UDP + (uint16_t) len_udp;
-
-  /* keep only the last 16 bits of the 32 bit calculated sum and add the carries */
-  while (sum >> 16)
-    sum = (sum & 0xFFFF) + (sum >> 16);
-		
-  /* Take the one's complement of sum */
-  return ((uint16_t) ~sum);
+    uint16_t word16;
+    uint32_t sum = 0;
+    int i;
+
+    /* make 16 bit words out of every two adjacent 8 bit words and  */
+    /* calculate the sum of all 16 bit words */
+    for (i = 0; i < len_udp; i += 2) {
+        word16 = ((buf[i] << 8) & 0xFF00) + ((i + 1 < len_udp) ? (buf[i+1] & 0xFF) : 0);
+        sum += word16;
+    }
+
+    /* add the UDP pseudo header which contains the IP source and destination addresses */
+    for (i = 0; i < 4; i += 2) {
+        word16 = ((src_addr[i] << 8) & 0xFF00) + (src_addr[i+1] & 0xFF);
+        sum += word16;
+    }
+    for (i = 0; i < 4; i += 2) {
+        word16 = ((dest_addr[i] << 8) & 0xFF00) + (dest_addr[i+1] & 0xFF);
+        sum += word16;
+    }
+
+    /* the protocol number and the length of the UDP packet */
+    sum += (uint16_t) OPENVPN_IPPROTO_UDP + (uint16_t) len_udp;
+
+    /* keep only the last 16 bits of the 32 bit calculated sum and add the carries */
+    while (sum >> 16)
+        sum = (sum & 0xFFFF) + (sum >> 16);
+
+    /* Take the one's complement of sum */
+    return ((uint16_t) ~sum);
 }
 
 in_addr_t
-dhcp_extract_router_msg (struct buffer *ipbuf)
+dhcp_extract_router_msg(struct buffer *ipbuf)
 {
-  struct dhcp_full *df = (struct dhcp_full *) BPTR (ipbuf);
-  const int optlen = BLEN (ipbuf) - (sizeof (struct openvpn_iphdr) + sizeof (struct openvpn_udphdr) + sizeof (struct dhcp));
-
-  if (optlen >= 0
-      && df->ip.protocol == OPENVPN_IPPROTO_UDP
-      && df->udp.source == htons (BOOTPS_PORT)
-      && df->udp.dest == htons (BOOTPC_PORT)
-      && df->dhcp.op == BOOTREPLY)
+    struct dhcp_full *df = (struct dhcp_full *) BPTR(ipbuf);
+    const int optlen = BLEN(ipbuf) - (sizeof(struct openvpn_iphdr) + sizeof(struct openvpn_udphdr) + sizeof(struct dhcp));
+
+    if (optlen >= 0
+        && df->ip.protocol == OPENVPN_IPPROTO_UDP
+        && df->udp.source == htons(BOOTPS_PORT)
+        && df->udp.dest == htons(BOOTPC_PORT)
+        && df->dhcp.op == BOOTREPLY)
     {
-      const int message_type = get_dhcp_message_type (&df->dhcp, optlen);
-      if (message_type == DHCPACK || message_type == DHCPOFFER)
-	{
-	  /* get the router IP address while padding out all DHCP router options */
-	  const in_addr_t ret = do_extract (&df->dhcp, optlen);
-
-	  /* recompute the UDP checksum */
-	  df->udp.check = 0;
-	  df->udp.check = htons (udp_checksum ((uint8_t *) &df->udp, 
-					       sizeof (struct openvpn_udphdr) + sizeof (struct dhcp) + optlen,
-					       (uint8_t *)&df->ip.saddr,
-					       (uint8_t *)&df->ip.daddr));
-
-	  /* only return the extracted Router address if DHCPACK */
-	  if (message_type == DHCPACK)
-	    {
-	      if (ret)
-		{
-		  struct gc_arena gc = gc_new ();
-		  msg (D_ROUTE, "Extracted DHCP router address: %s", print_in_addr_t (ret, 0, &gc));
-		  gc_free (&gc);
-		}
-
-	      return ret;
-	    }
-	}
+        const int message_type = get_dhcp_message_type(&df->dhcp, optlen);
+        if (message_type == DHCPACK || message_type == DHCPOFFER)
+        {
+            /* get the router IP address while padding out all DHCP router options */
+            const in_addr_t ret = do_extract(&df->dhcp, optlen);
+
+            /* recompute the UDP checksum */
+            df->udp.check = 0;
+            df->udp.check = htons(udp_checksum((uint8_t *) &df->udp,
+                                               sizeof(struct openvpn_udphdr) + sizeof(struct dhcp) + optlen,
+                                               (uint8_t *)&df->ip.saddr,
+                                               (uint8_t *)&df->ip.daddr));
+
+            /* only return the extracted Router address if DHCPACK */
+            if (message_type == DHCPACK)
+            {
+                if (ret)
+                {
+                    struct gc_arena gc = gc_new();
+                    msg(D_ROUTE, "Extracted DHCP router address: %s", print_in_addr_t(ret, 0, &gc));
+                    gc_free(&gc);
+                }
+
+                return ret;
+            }
+        }
     }
-  return 0;
+    return 0;
 }