diff mbox series

[bpf-next,1/2] bpf: add CHECKSUM_COMPLETE to bpf test progs

Message ID 20240522145712.3523593-1-vadfed@meta.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series [bpf-next,1/2] bpf: add CHECKSUM_COMPLETE to bpf test progs | expand

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Commit Message

Vadim Fedorenko May 22, 2024, 2:57 p.m. UTC 
Add special flag to validate that TC BPF program properly updates
checksum information in skb.

Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
---
 include/uapi/linux/bpf.h       |  2 ++
 net/bpf/test_run.c             | 19 ++++++++++++++++++-
 tools/include/uapi/linux/bpf.h |  2 ++
 3 files changed, 22 insertions(+), 1 deletion(-)

Comments

Simon Horman May 22, 2024, 6:32 p.m. UTC | #1 
On Wed, May 22, 2024 at 07:57:10AM -0700, Vadim Fedorenko wrote:
> Add special flag to validate that TC BPF program properly updates
> checksum information in skb.
> 
> Signed-off-by: Vadim Fedorenko <vadfed@meta.com>

...

> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> index f6aad4ed2ab2..841552785c65 100644
> --- a/net/bpf/test_run.c
> +++ b/net/bpf/test_run.c
> @@ -974,10 +974,13 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
>  	int hh_len = ETH_HLEN;
>  	struct sk_buff *skb;
>  	struct sock *sk;
> +	__wsum csum;
> +	__sum16 sum;

Hi Vadim,

sum seems to be is unused in this function.
And, fwiiw, the scope of csum looks like it could be reduced.

>  	void *data;
>  	int ret;
>  
> -	if (kattr->test.flags || kattr->test.cpu || kattr->test.batch_size)
> +	if ((kattr->test.flags & ~BPF_F_TEST_SKB_CHECKSUM_COMPLETE) ||
> +	    kattr->test.cpu || kattr->test.batch_size)
>  		return -EINVAL;
>  
>  	data = bpf_test_init(kattr, kattr->test.data_size_in,
> @@ -1025,6 +1028,12 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
>  
>  	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
>  	__skb_put(skb, size);
> +
> +	if (kattr->test.flags & BPF_F_TEST_SKB_CHECKSUM_COMPLETE) {
> +		skb->csum = skb_checksum(skb, 0, skb->len, 0);
> +		skb->ip_summed = CHECKSUM_COMPLETE;
> +	}
> +
>  	if (ctx && ctx->ifindex > 1) {
>  		dev = dev_get_by_index(net, ctx->ifindex);
>  		if (!dev) {
> @@ -1079,6 +1088,14 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
>  	}
>  	convert_skb_to___skb(skb, ctx);
>  
> +	if (kattr->test.flags & BPF_F_TEST_SKB_CHECKSUM_COMPLETE) {
> +		csum = skb_checksum(skb, 0, skb->len, 0);
> +		if (skb->csum != csum) {
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +	}
> +
>  	size = skb->len;
>  	/* bpf program can never convert linear skb to non-linear */
>  	if (WARN_ON_ONCE(skb_is_nonlinear(skb)))

...
Vadim Fedorenko May 22, 2024, 9:21 p.m. UTC | #2 
On 22/05/2024 19:32, Simon Horman wrote:
> On Wed, May 22, 2024 at 07:57:10AM -0700, Vadim Fedorenko wrote:
>> Add special flag to validate that TC BPF program properly updates
>> checksum information in skb.
>>
>> Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
> 
> ...
> 
>> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
>> index f6aad4ed2ab2..841552785c65 100644
>> --- a/net/bpf/test_run.c
>> +++ b/net/bpf/test_run.c
>> @@ -974,10 +974,13 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
>>   	int hh_len = ETH_HLEN;
>>   	struct sk_buff *skb;
>>   	struct sock *sk;
>> +	__wsum csum;
>> +	__sum16 sum;
> 
> Hi Vadim,
> 
> sum seems to be is unused in this function.
> And, fwiiw, the scope of csum looks like it could be reduced.

Ah, leftover from previous iteration, thanks for catching it!
Ok, I'll move csum to the "if" block in v2.

>>   	void *data;
>>   	int ret;
>>   
>> -	if (kattr->test.flags || kattr->test.cpu || kattr->test.batch_size)
>> +	if ((kattr->test.flags & ~BPF_F_TEST_SKB_CHECKSUM_COMPLETE) ||
>> +	    kattr->test.cpu || kattr->test.batch_size)
>>   		return -EINVAL;
>>   
>>   	data = bpf_test_init(kattr, kattr->test.data_size_in,
>> @@ -1025,6 +1028,12 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
>>   
>>   	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
>>   	__skb_put(skb, size);
>> +
>> +	if (kattr->test.flags & BPF_F_TEST_SKB_CHECKSUM_COMPLETE) {
>> +		skb->csum = skb_checksum(skb, 0, skb->len, 0);
>> +		skb->ip_summed = CHECKSUM_COMPLETE;
>> +	}
>> +
>>   	if (ctx && ctx->ifindex > 1) {
>>   		dev = dev_get_by_index(net, ctx->ifindex);
>>   		if (!dev) {
>> @@ -1079,6 +1088,14 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
>>   	}
>>   	convert_skb_to___skb(skb, ctx);
>>   
>> +	if (kattr->test.flags & BPF_F_TEST_SKB_CHECKSUM_COMPLETE) {
>> +		csum = skb_checksum(skb, 0, skb->len, 0);
>> +		if (skb->csum != csum) {
>> +			ret = -EINVAL;
>> +			goto out;
>> +		}
>> +	}
>> +
>>   	size = skb->len;
>>   	/* bpf program can never convert linear skb to non-linear */
>>   	if (WARN_ON_ONCE(skb_is_nonlinear(skb)))
> 
> ...
kernel test robot May 23, 2024, 2:22 p.m. UTC | #3 
Hi Vadim,

kernel test robot noticed the following build warnings:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Vadim-Fedorenko/selftests-bpf-validate-CHECKSUM_COMPLETE-option/20240522-225856
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20240522145712.3523593-1-vadfed%40meta.com
patch subject: [PATCH bpf-next 1/2] bpf: add CHECKSUM_COMPLETE to bpf test progs
config: arm64-defconfig (https://download.01.org/0day-ci/archive/20240523/202405232220.e9PuO2yW-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240523/202405232220.e9PuO2yW-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405232220.e9PuO2yW-lkp@intel.com/

All warnings (new ones prefixed by >>):

   net/bpf/test_run.c: In function 'bpf_prog_test_run_skb':
>> net/bpf/test_run.c:978:17: warning: unused variable 'sum' [-Wunused-variable]
     978 |         __sum16 sum;
         |                 ^~~


vim +/sum +978 net/bpf/test_run.c

   963	
   964	int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
   965				  union bpf_attr __user *uattr)
   966	{
   967		bool is_l2 = false, is_direct_pkt_access = false;
   968		struct net *net = current->nsproxy->net_ns;
   969		struct net_device *dev = net->loopback_dev;
   970		u32 size = kattr->test.data_size_in;
   971		u32 repeat = kattr->test.repeat;
   972		struct __sk_buff *ctx = NULL;
   973		u32 retval, duration;
   974		int hh_len = ETH_HLEN;
   975		struct sk_buff *skb;
   976		struct sock *sk;
   977		__wsum csum;
 > 978		__sum16 sum;
   979		void *data;
   980		int ret;
   981	
   982		if ((kattr->test.flags & ~BPF_F_TEST_SKB_CHECKSUM_COMPLETE) ||
   983		    kattr->test.cpu || kattr->test.batch_size)
   984			return -EINVAL;
   985	
   986		data = bpf_test_init(kattr, kattr->test.data_size_in,
   987				     size, NET_SKB_PAD + NET_IP_ALIGN,
   988				     SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
   989		if (IS_ERR(data))
   990			return PTR_ERR(data);
   991	
   992		ctx = bpf_ctx_init(kattr, sizeof(struct __sk_buff));
   993		if (IS_ERR(ctx)) {
   994			kfree(data);
   995			return PTR_ERR(ctx);
   996		}
   997	
   998		switch (prog->type) {
   999		case BPF_PROG_TYPE_SCHED_CLS:
  1000		case BPF_PROG_TYPE_SCHED_ACT:
  1001			is_l2 = true;
  1002			fallthrough;
  1003		case BPF_PROG_TYPE_LWT_IN:
  1004		case BPF_PROG_TYPE_LWT_OUT:
  1005		case BPF_PROG_TYPE_LWT_XMIT:
  1006			is_direct_pkt_access = true;
  1007			break;
  1008		default:
  1009			break;
  1010		}
  1011	
  1012		sk = sk_alloc(net, AF_UNSPEC, GFP_USER, &bpf_dummy_proto, 1);
  1013		if (!sk) {
  1014			kfree(data);
  1015			kfree(ctx);
  1016			return -ENOMEM;
  1017		}
  1018		sock_init_data(NULL, sk);
  1019	
  1020		skb = slab_build_skb(data);
  1021		if (!skb) {
  1022			kfree(data);
  1023			kfree(ctx);
  1024			sk_free(sk);
  1025			return -ENOMEM;
  1026		}
  1027		skb->sk = sk;
  1028	
  1029		skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
  1030		__skb_put(skb, size);
  1031	
  1032		if (kattr->test.flags & BPF_F_TEST_SKB_CHECKSUM_COMPLETE) {
  1033			skb->csum = skb_checksum(skb, 0, skb->len, 0);
  1034			skb->ip_summed = CHECKSUM_COMPLETE;
  1035		}
  1036	
  1037		if (ctx && ctx->ifindex > 1) {
  1038			dev = dev_get_by_index(net, ctx->ifindex);
  1039			if (!dev) {
  1040				ret = -ENODEV;
  1041				goto out;
  1042			}
  1043		}
  1044		skb->protocol = eth_type_trans(skb, dev);
  1045		skb_reset_network_header(skb);
  1046	
  1047		switch (skb->protocol) {
  1048		case htons(ETH_P_IP):
  1049			sk->sk_family = AF_INET;
  1050			if (sizeof(struct iphdr) <= skb_headlen(skb)) {
  1051				sk->sk_rcv_saddr = ip_hdr(skb)->saddr;
  1052				sk->sk_daddr = ip_hdr(skb)->daddr;
  1053			}
  1054			break;
  1055	#if IS_ENABLED(CONFIG_IPV6)
  1056		case htons(ETH_P_IPV6):
  1057			sk->sk_family = AF_INET6;
  1058			if (sizeof(struct ipv6hdr) <= skb_headlen(skb)) {
  1059				sk->sk_v6_rcv_saddr = ipv6_hdr(skb)->saddr;
  1060				sk->sk_v6_daddr = ipv6_hdr(skb)->daddr;
  1061			}
  1062			break;
  1063	#endif
  1064		default:
  1065			break;
  1066		}
  1067	
  1068		if (is_l2)
  1069			__skb_push(skb, hh_len);
  1070		if (is_direct_pkt_access)
  1071			bpf_compute_data_pointers(skb);
  1072		ret = convert___skb_to_skb(skb, ctx);
  1073		if (ret)
  1074			goto out;
  1075		ret = bpf_test_run(prog, skb, repeat, &retval, &duration, false);
  1076		if (ret)
  1077			goto out;
  1078		if (!is_l2) {
  1079			if (skb_headroom(skb) < hh_len) {
  1080				int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb));
  1081	
  1082				if (pskb_expand_head(skb, nhead, 0, GFP_USER)) {
  1083					ret = -ENOMEM;
  1084					goto out;
  1085				}
  1086			}
  1087			memset(__skb_push(skb, hh_len), 0, hh_len);
  1088		}
  1089		convert_skb_to___skb(skb, ctx);
  1090	
  1091		if (kattr->test.flags & BPF_F_TEST_SKB_CHECKSUM_COMPLETE) {
  1092			csum = skb_checksum(skb, 0, skb->len, 0);
  1093			if (skb->csum != csum) {
  1094				ret = -EINVAL;
  1095				goto out;
  1096			}
  1097		}
  1098	
  1099		size = skb->len;
  1100		/* bpf program can never convert linear skb to non-linear */
  1101		if (WARN_ON_ONCE(skb_is_nonlinear(skb)))
  1102			size = skb_headlen(skb);
  1103		ret = bpf_test_finish(kattr, uattr, skb->data, NULL, size, retval,
  1104				      duration);
  1105		if (!ret)
  1106			ret = bpf_ctx_finish(kattr, uattr, ctx,
  1107					     sizeof(struct __sk_buff));
  1108	out:
  1109		if (dev && dev != net->loopback_dev)
  1110			dev_put(dev);
  1111		kfree_skb(skb);
  1112		sk_free(sk);
  1113		kfree(ctx);
  1114		return ret;
  1115	}
  1116
diff mbox series

Patch

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 90706a47f6ff..f7d458d88111 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1425,6 +1425,8 @@  enum {
 #define BPF_F_TEST_RUN_ON_CPU	(1U << 0)
 /* If set, XDP frames will be transmitted after processing */
 #define BPF_F_TEST_XDP_LIVE_FRAMES	(1U << 1)
+/* If set, apply CHECKSUM_COMPLETE to skb and validate the checksum */
+#define BPF_F_TEST_SKB_CHECKSUM_COMPLETE	(1U << 2)
 
 /* type for BPF_ENABLE_STATS */
 enum bpf_stats_type {
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index f6aad4ed2ab2..841552785c65 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -974,10 +974,13 @@  int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
 	int hh_len = ETH_HLEN;
 	struct sk_buff *skb;
 	struct sock *sk;
+	__wsum csum;
+	__sum16 sum;
 	void *data;
 	int ret;
 
-	if (kattr->test.flags || kattr->test.cpu || kattr->test.batch_size)
+	if ((kattr->test.flags & ~BPF_F_TEST_SKB_CHECKSUM_COMPLETE) ||
+	    kattr->test.cpu || kattr->test.batch_size)
 		return -EINVAL;
 
 	data = bpf_test_init(kattr, kattr->test.data_size_in,
@@ -1025,6 +1028,12 @@  int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
 
 	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
 	__skb_put(skb, size);
+
+	if (kattr->test.flags & BPF_F_TEST_SKB_CHECKSUM_COMPLETE) {
+		skb->csum = skb_checksum(skb, 0, skb->len, 0);
+		skb->ip_summed = CHECKSUM_COMPLETE;
+	}
+
 	if (ctx && ctx->ifindex > 1) {
 		dev = dev_get_by_index(net, ctx->ifindex);
 		if (!dev) {
@@ -1079,6 +1088,14 @@  int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
 	}
 	convert_skb_to___skb(skb, ctx);
 
+	if (kattr->test.flags & BPF_F_TEST_SKB_CHECKSUM_COMPLETE) {
+		csum = skb_checksum(skb, 0, skb->len, 0);
+		if (skb->csum != csum) {
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
 	size = skb->len;
 	/* bpf program can never convert linear skb to non-linear */
 	if (WARN_ON_ONCE(skb_is_nonlinear(skb)))
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 90706a47f6ff..f7d458d88111 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1425,6 +1425,8 @@  enum {
 #define BPF_F_TEST_RUN_ON_CPU	(1U << 0)
 /* If set, XDP frames will be transmitted after processing */
 #define BPF_F_TEST_XDP_LIVE_FRAMES	(1U << 1)
+/* If set, apply CHECKSUM_COMPLETE to skb and validate the checksum */
+#define BPF_F_TEST_SKB_CHECKSUM_COMPLETE	(1U << 2)
 
 /* type for BPF_ENABLE_STATS */
 enum bpf_stats_type {