From bd08ae67f9a0cae2ce15be885254cad9449d4551 Mon Sep 17 00:00:00 2001

From: Simon Kelley <simon@thekelleys.org.uk>

Date: Fri, 19 Apr 2013 10:22:06 +0100

Subject: [PATCH] Allow option number zero in encapsulated DHCP options.

---

 src/dhcp-common.c |  6 +++---

 src/dnsmasq.h     |  4 ++--

 src/option.c      | 33 ++++++++++++++++++++-------------

 3 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/src/dhcp-common.c b/src/dhcp-common.c

index f4fd088..8de4268 100644

--- a/src/dhcp-common.c

+++ b/src/dhcp-common.c

@@ -512,7 +512,7 @@ void display_opts6(void)

 }

 #endif

-u16 lookup_dhcp_opt(int prot, char *name)

+int lookup_dhcp_opt(int prot, char *name)

 {

   const struct opttab_t *t;

   int i;

@@ -528,10 +528,10 @@ u16 lookup_dhcp_opt(int prot, char *name)

     if (strcasecmp(t[i].name, name) == 0)

       return t[i].val;

-  return 0;

+  return -1;

 }

-u16 lookup_dhcp_len(int prot, u16 val)

+int lookup_dhcp_len(int prot, int val)

 {

   const struct opttab_t *t;

   int i;

diff --git a/src/dnsmasq.h b/src/dnsmasq.h

index 69ae7a7..41e2798 100644

--- a/src/dnsmasq.h

+++ b/src/dnsmasq.h

@@ -1216,8 +1216,8 @@ void log_tags(struct dhcp_netid *netid, u32 xid);

 int match_bytes(struct dhcp_opt *o, unsigned char *p, int len);

 void dhcp_update_configs(struct dhcp_config *configs);

 void display_opts(void);

-u16 lookup_dhcp_opt(int prot, char *name);

-u16 lookup_dhcp_len(int prot, u16 val);

+int lookup_dhcp_opt(int prot, char *name);

+int lookup_dhcp_len(int prot, int val);

 char *option_string(int prot, unsigned int opt, unsigned char *val, 

 		    int opt_len, char *buf, int buf_len);

 #ifdef HAVE_LINUX_NETWORK

diff --git a/src/option.c b/src/option.c

index b2596ec..2a61017 100644

--- a/src/option.c

+++ b/src/option.c

@@ -750,6 +750,7 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)

   struct dhcp_netid *np = NULL;

   u16 opt_len = 0;

   int is6 = 0;

+  int option_ok = 0;

   new->len = 0;

   new->flags = flags;

@@ -769,16 +770,19 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)

 	{

 	  new->opt = atoi(arg);

 	  opt_len = 0;

+	  option_ok = 1;

 	  break;

 	}

       if (strstr(arg, "option:") == arg)

 	{

-	  new->opt = lookup_dhcp_opt(AF_INET, arg+7);

-	  opt_len = lookup_dhcp_len(AF_INET, new->opt);

-	  /* option:<optname> must follow tag and vendor string. */

-	  if ((opt_len & OT_INTERNAL) && flags != DHOPT_MATCH)

-	    new->opt = 0;

+	  if ((new->opt = lookup_dhcp_opt(AF_INET, arg+7)) != -1)

+	    {

+	      opt_len = lookup_dhcp_len(AF_INET, new->opt);

+	      /* option:<optname> must follow tag and vendor string. */

+	      if (!(opt_len & OT_INTERNAL) || flags == DHOPT_MATCH)

+		option_ok = 1;

+	    }

 	  break;

 	}

 #ifdef HAVE_DHCP6

@@ -792,13 +796,16 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)

 	    {

 	      new->opt = atoi(arg+8);

 	      opt_len = 0;

+	      option_ok = 1;

 	    }

 	  else

 	    {

-	      new->opt = lookup_dhcp_opt(AF_INET6, arg+8);

-	      opt_len = lookup_dhcp_len(AF_INET6, new->opt);

-	      if ((opt_len & OT_INTERNAL) && flags != DHOPT_MATCH)

-		new->opt = 0;

+	      if ((new->opt = lookup_dhcp_opt(AF_INET6, arg+8)) != -1)

+		{

+		  opt_len = lookup_dhcp_len(AF_INET6, new->opt);

+		  if (!(opt_len & OT_INTERNAL) || flags == DHOPT_MATCH)

+		    option_ok = 1;

+		}

 	    }

 	  /* option6:<opt>|<optname> must follow tag and vendor string. */

 	  is6 = 1;

@@ -821,7 +828,7 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)

 	  new->flags |= DHOPT_RFC3925;

 	  if (flags == DHOPT_MATCH)

 	    {

-	      new->opt = 1; /* avoid error below */

+	      option_ok = 1;

 	      break;

 	    }

 	}

@@ -848,16 +855,16 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)

       if (opt_len == 0 &&

 	  !(new->flags & DHOPT_RFC3925))

-	opt_len = lookup_dhcp_len(AF_INET6 ,new->opt);

+	opt_len = lookup_dhcp_len(AF_INET6, new->opt);

     }

   else

 #endif

     if (opt_len == 0 &&

 	!(new->flags & (DHOPT_VENDOR | DHOPT_ENCAPSULATE | DHOPT_RFC3925)))

-      opt_len = lookup_dhcp_len(AF_INET ,new->opt);

+      opt_len = lookup_dhcp_len(AF_INET, new->opt);

   /* option may be missing with rfc3925 match */

-  if (new->opt == 0)

+  if (!option_ok)

     ret_err(_("bad dhcp-option"));

   if (comma)

-- 

1.8.1.4