[PATCH 1/2] iproute2: tc/m_pedit.c - remove dead code

[PATCH 1/2] iproute2: tc/m_pedit.c - remove dead code

[Maciej Żenczykowski]

From: Maciej Żenczykowski <maze@google.com>

The initializers are simply not needed.

These if-blocks are outright dead code, because '0 > unsigned' is always
false, so only else clause triggers and regardless of which clause triggers
it only updates 'ind' which is later unconditionally written to before
being used anyway.

Otherwise we get errors from clang:

  m_pedit.c:166:8: error: comparison of 0 > unsigned expression is always false [-Werror,-Wtautological-compare]
    if (0 > tkey->off) {
        ~ ^ ~~~~~~~~~
  m_pedit.c:209:8: error: comparison of 0 > unsigned expression is always false [-Werror,-Wtautological-compare]
    if (0 > tkey->off) {
        ~ ^ ~~~~~~~~~
  2 errors generated.

Change-Id: I3c9e9092915088fc56f992e5df736851541a4458
---
 tc/m_pedit.c | 32 ++++++++------------------------
 1 file changed, 8 insertions(+), 24 deletions(-)

diff --git a/tc/m_pedit.c b/tc/m_pedit.c
index dfe9b2ebd6e0..4fdd189d7d9c 100644
--- a/tc/m_pedit.c
+++ b/tc/m_pedit.c
@@ -160,17 +160,9 @@ pack_key32(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
 int
 pack_key16(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
 {
-	int ind = 0, stride = 0;
+	int ind, stride;
 	__u32 m[4] = {0xFFFF0000,0xFF0000FF,0x0000FFFF};
 
-	if (0 > tkey->off) {
-		ind = tkey->off + 1;
-		if (0 > ind)
-			ind = -1*ind;
-	} else {
-		ind = tkey->off;
-	}
-
 	if (tkey->val > 0xFFFF || tkey->mask > 0xFFFF) {
 		fprintf(stderr, "pack_key16 bad value\n");
 		return -1;
@@ -178,18 +170,16 @@ pack_key16(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
 
 	ind = tkey->off & 3;
 
-	if (0 > ind || 2 < ind) {
+	if (ind == 3) {
 		fprintf(stderr, "pack_key16 bad index value %d\n",ind);
 		return -1;
 	}
 
 	stride = 8 * ind;
 	tkey->val = htons(tkey->val);
-	if (stride > 0) {
-		tkey->val <<= stride;
-		tkey->mask <<= stride;
-		retain <<= stride;
-	}
+	tkey->val <<= stride;
+	tkey->mask <<= stride;
+	retain <<= stride;
 	tkey->mask = retain|m[ind];
 
 	tkey->off &= ~3;
@@ -203,28 +193,22 @@ pack_key16(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
 int
 pack_key8(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
 {
-	int ind = 0, stride = 0;
+	int ind, stride;
 	__u32 m[4] = {0xFFFFFF00,0xFFFF00FF,0xFF00FFFF,0x00FFFFFF};
 
-	if (0 > tkey->off) {
-		ind = tkey->off + 1;
-		if (0 > ind)
-			ind = -1*ind;
-	} else {
-		ind = tkey->off;
-	}
-
 	if (tkey->val > 0xFF || tkey->mask > 0xFF) {
 		fprintf(stderr, "pack_key8 bad value (val %x mask %x\n", tkey->val, tkey->mask);
 		return -1;
 	}
 
 	ind = tkey->off & 3;
+
 	stride = 8 * ind;
 	tkey->val <<= stride;
 	tkey->mask <<= stride;
 	retain <<= stride;
 	tkey->mask = retain|m[ind];
+
 	tkey->off &= ~3;
 
 	if (pedit_debug)
-- 
2.4.3.573.g4eafbef

[PATCH 2/2] iproute2: misc/ss.c - fix run_ssfilter af_packet when protocol == 0

[Maciej Żenczykowski]

From: Maciej Żenczykowski <maze@google.com>

s->local.data is a pointer to a field of a non-NULL struct, and hence
cannot be NULL, thus comparing it to 0 is always false, and thus the
return is always false.

Presumably this was meant to be a check whether s->local.data[0] (which
I believe stores af_packet protocol) is 0, ie. ANY.

Change-Id: Ia232f5b06ce081e3b2fb6338f1a709cd94e03ae5
Fixes:
  ss.c:1018:37: error: comparison of array 's->local.data' equal to a null pointer is always false [-Werror,-Wtautological-pointer-compare]
    return s->lport == 0 && s->local.data == 0;
                            ~~~~~~~~~^~~~    ~
  1 error generated.
---
 misc/ss.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/misc/ss.c b/misc/ss.c
index dba0901791c7..36b0efdfd32f 100644
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -1090,7 +1090,7 @@ static int run_ssfilter(struct ssfilter *f, struct sockstat *s)
 					     strspn(p+1, "0123456789abcdef") == 5);
 		}
 		if (s->local.family == AF_PACKET)
-			return s->lport == 0 && s->local.data == 0;
+			return s->lport == 0 && s->local.data[0] == 0;
 		if (s->local.family == AF_NETLINK)
 			return s->lport < 0;
 
-- 
2.4.3.573.g4eafbef

Re: [PATCH 1/2] iproute2: tc/m_pedit.c - remove dead code

[Stephen Hemminger]

On Thu, 25 Jun 2015 02:03:02 -0700
Maciej Żenczykowski <zenczykowski@gmail.com> wrote:

> From: Maciej Żenczykowski <maze@google.com>
> 
> The initializers are simply not needed.
> 
> These if-blocks are outright dead code, because '0 > unsigned' is always
> false, so only else clause triggers and regardless of which clause triggers
> it only updates 'ind' which is later unconditionally written to before
> being used anyway.
> 
> Otherwise we get errors from clang:
> 
>   m_pedit.c:166:8: error: comparison of 0 > unsigned expression is always false [-Werror,-Wtautological-compare]
>     if (0 > tkey->off) {
>         ~ ^ ~~~~~~~~~
>   m_pedit.c:209:8: error: comparison of 0 > unsigned expression is always false [-Werror,-Wtautological-compare]
>     if (0 > tkey->off) {
>         ~ ^ ~~~~~~~~~
>   2 errors generated.
> 
> Change-Id: I3c9e9092915088fc56f992e5df736851541a4458
> ---
>  tc/m_pedit.c | 32 ++++++++------------------------
>  1 file changed, 8 insertions(+), 24 deletions(-)

Both applied