[PATCH] Remove Scope IDs from IPv6 addresses.

[PATCH] Remove Scope IDs from IPv6 addresses.

[Hleb Valoshka]

	Scoped ipv6 addresses are defined in rfc4007.
	Ruby doesn't support them yet and it's unknown whether it will
	(see http://bugs.ruby-lang.org/issues/8464).
	So we just remove scope ids.
---
 ext/raindrops/linux_inet_diag.c |   49 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 46 insertions(+), 3 deletions(-)

diff --git a/ext/raindrops/linux_inet_diag.c b/ext/raindrops/linux_inet_diag.c
index cd4a876..3948c33 100644
--- a/ext/raindrops/linux_inet_diag.c
+++ b/ext/raindrops/linux_inet_diag.c
@@ -134,17 +134,54 @@ static int st_free_data(st_data_t key, st_data_t value, st_data_t ignored)
 	return ST_DELETE;
 }
 
+/*
+ * call-seq:
+ *      remove_scope_id(ipv4_or_ipv6_address)
+ *
+ * Returns copy of IP address with Scope ID removed,
+ * if address has it (only IPv6 actually may have it).
+ *
+ * NOTE: free() must be called on its result.
+ */
+static char* remove_scope_id(const char * addr)
+{
+        char *newaddr, *t;
+
+        newaddr = strdup(addr);
+        if (newaddr == NULL)
+                perror("strdup");
+
+        t = strchr(newaddr, '%');
+
+        if (t != NULL) {
+                *t = '\0';
+                t = strchr(t+1, ']');
+                if (t == NULL)
+                        fprintf(stderr, "Bad IPv6 address: %s!\n", addr);
+                else
+                        strcat(newaddr, t);
+        }
+
+        return newaddr;
+}
+
 static int st_to_hash(st_data_t key, st_data_t value, VALUE hash)
 {
 	struct listen_stats *stats = (struct listen_stats *)value;
 
 	if (stats->listener_p) {
-		VALUE k = rb_str_new2((const char *)key);
-		VALUE v = rb_listen_stats(stats);
+		VALUE k, v;
+		char *xkey = remove_scope_id((const char *)key);
+		if (xkey == NULL)
+			goto get_out;
+		k = rb_str_new2(xkey);
+		v = rb_listen_stats(stats);
+		free(xkey);
 
 		OBJ_FREEZE(k);
 		rb_hash_aset(hash, k, v);
 	}
+get_out:
 	return st_free_data(key, value, 0);
 }
 
@@ -153,7 +190,12 @@ static int st_AND_hash(st_data_t key, st_data_t value, VALUE hash)
 	struct listen_stats *stats = (struct listen_stats *)value;
 
 	if (stats->listener_p) {
-		VALUE k = rb_str_new2((const char *)key);
+		VALUE k;
+		char *xkey = remove_scope_id((const char *)key);
+		if (xkey == NULL)
+			goto get_out;
+		k = rb_str_new2(xkey);
+		free(xkey);
 
 		if (rb_hash_lookup(hash, k) == Qtrue) {
 			VALUE v = rb_listen_stats(stats);
@@ -161,6 +203,7 @@ static int st_AND_hash(st_data_t key, st_data_t value, VALUE hash)
 			rb_hash_aset(hash, k, v);
 		}
 	}
+get_out:
 	return st_free_data(key, value, 0);
 }
 
-- 
1.7.10.4

Re: [PATCH] Remove Scope IDs from IPv6 addresses.

[Eric Wong]

Hleb Valoshka <375gnu@gmail.com> wrote:
> 	Scoped ipv6 addresses are defined in rfc4007.
> 	Ruby doesn't support them yet and it's unknown whether it will
> 	(see http://bugs.ruby-lang.org/issues/8464).
> 	So we just remove scope ids.

Thanks.  Comments inline.

> --- a/ext/raindrops/linux_inet_diag.c
> +++ b/ext/raindrops/linux_inet_diag.c
> @@ -134,17 +134,54 @@ static int st_free_data(st_data_t key, st_data_t value, st_data_t ignored)

> +static char* remove_scope_id(const char * addr)
> +{
> +        char *newaddr, *t;
> +
> +        newaddr = strdup(addr);
> +        if (newaddr == NULL)
> +                perror("strdup");

We'll segfault on strchr below if we perrored above.  If we continue
using strdup, I would just use ruby_strdup() (works on both MRI/rbx).

But I'd rather avoid *strdup entirely.  This is unlikely to
remove, right?

> +        t = strchr(newaddr, '%');
> +
> +        if (t != NULL) {
> +                *t = '\0';
> +                t = strchr(t+1, ']');
> +                if (t == NULL)
> +                        fprintf(stderr, "Bad IPv6 address: %s!\n", addr);

Better to use rb_warn/rb_warning.
These are preferable since they allow assigning $stderr to StringIO and
such.  But if we don't use strdup, maybe we could raise instead.

> +                else
> +                        strcat(newaddr, t);
> +        }
> +
> +        return newaddr;
> +}

Perhaps something like this (totally untested, likely off-by-one errors)

static VALUE remove_scope_id(const char *addr)
{
	VALUE rv = rb_str_new2(addr);
	long len = RSTRING_LEN(rv);
	char *ptr = RSTRING_PTR(rv);
	char *pct = memchr(ptr, '%', len);

	/*
	 * remove scoped portion
	 * Ruby equivalent: rv.sub!(/%([^\]]*)\]/, "]")
	 */
	if (pct) {
		long newlen = pct - ptr;
		char *rbracket = memchr(pct, ']', len - newlen);

		if (rbracket) {
			size_t move = len - (rbracket - ptr);

			memmove(pct, rbracket, move);
			newlen += move;

			rb_str_set_len(rv, newlen);
		} else {
			/* perhaps raise here? */
			rb_warn("Bad IPv6 address: %s", addr);
		}
	}
	return rv;
}

Re: [PATCH] Remove Scope IDs from IPv6 addresses.

[Eric Wong]

I just noticed this is the wrong list, please redirect all comments
to raindrops@librelist.org  Thanks.

[PATCH] Remove Scope IDs from IPv6 addresses.

[Hleb Valoshka]

	Scoped ipv6 addresses are defined in rfc4007.
	Ruby doesn't support them yet and it's unknown whether it will
	(see http://bugs.ruby-lang.org/issues/8464).
	So we just remove scope ids.

	Tested with MRI and Rubinius.
---
 ext/raindrops/linux_inet_diag.c |   41 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/ext/raindrops/linux_inet_diag.c b/ext/raindrops/linux_inet_diag.c
index cd4a876..7b5bae1 100644
--- a/ext/raindrops/linux_inet_diag.c
+++ b/ext/raindrops/linux_inet_diag.c
@@ -134,12 +134,49 @@ static int st_free_data(st_data_t key, st_data_t value, st_data_t ignored)
 	return ST_DELETE;
 }
 
+/*
+ * call-seq:
+ *      remove_scope_id(ip_address)
+ *
+ * Returns copy of IP address with Scope ID removed,
+ * if address has it (only IPv6 actually may have it).
+ */
+static VALUE remove_scope_id(const char *addr)
+{
+	VALUE rv = rb_str_new2(addr);
+	long len = RSTRING_LEN(rv);
+	char *ptr = RSTRING_PTR(rv);
+	char *pct = memchr(ptr, '%', len);
+
+	/*
+	 * remove scoped portion
+	 * Ruby equivalent: rv.sub!(/%([^\]]*)\]/, "]")
+	 */
+	if (pct) {
+		size_t newlen = pct - ptr;
+		char *rbracket = memchr(pct, ']', len - newlen);
+
+		if (rbracket) {
+			size_t move = len - (rbracket - ptr);
+
+			memmove(pct, rbracket, move);
+			newlen += move;
+
+			rb_str_set_len(rv, newlen);
+		} else {
+			rb_raise(rb_eArgError,
+				"']' not found in IPv6 addr=%s", ptr);
+                }
+        }
+        return rv;
+}
+
 static int st_to_hash(st_data_t key, st_data_t value, VALUE hash)
 {
 	struct listen_stats *stats = (struct listen_stats *)value;
 
 	if (stats->listener_p) {
-		VALUE k = rb_str_new2((const char *)key);
+		VALUE k = remove_scope_id((const char *)key);
 		VALUE v = rb_listen_stats(stats);
 
 		OBJ_FREEZE(k);
@@ -153,7 +190,7 @@ static int st_AND_hash(st_data_t key, st_data_t value, VALUE hash)
 	struct listen_stats *stats = (struct listen_stats *)value;
 
 	if (stats->listener_p) {
-		VALUE k = rb_str_new2((const char *)key);
+		VALUE k = remove_scope_id((const char *)key);
 
 		if (rb_hash_lookup(hash, k) == Qtrue) {
 			VALUE v = rb_listen_stats(stats);
-- 
1.7.10.4