* [bpf-next, v2] samples: bpf: add max_pckt_size option at xdp_adjust_tail
@ 2019-08-26 16:25 Daniel T. Lee
2019-08-29 20:41 ` Song Liu
0 siblings, 1 reply; 4+ messages in thread
From: Daniel T. Lee @ 2019-08-26 16:25 UTC (permalink / raw)
To: Daniel Borkmann, Alexei Starovoitov; +Cc: netdev
Currently, at xdp_adjust_tail_kern.c, MAX_PCKT_SIZE is limited
to 600. To make this size flexible, a new map 'pcktsz' is added.
By updating new packet size to this map from the userland,
xdp_adjust_tail_kern.o will use this value as a new max_pckt_size.
If no '-P <MAX_PCKT_SIZE>' option is used, the size of maximum packet
will be 600 as a default.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
---
Changes in v2:
- Change the helper to fetch map from 'bpf_map__next' to
'bpf_object__find_map_fd_by_name'.
samples/bpf/xdp_adjust_tail_kern.c | 23 +++++++++++++++++++----
samples/bpf/xdp_adjust_tail_user.c | 27 +++++++++++++++++++++------
2 files changed, 40 insertions(+), 10 deletions(-)
diff --git a/samples/bpf/xdp_adjust_tail_kern.c b/samples/bpf/xdp_adjust_tail_kern.c
index 411fdb21f8bc..d6d84ffe6a7a 100644
--- a/samples/bpf/xdp_adjust_tail_kern.c
+++ b/samples/bpf/xdp_adjust_tail_kern.c
@@ -25,6 +25,13 @@
#define ICMP_TOOBIG_SIZE 98
#define ICMP_TOOBIG_PAYLOAD_SIZE 92
+struct bpf_map_def SEC("maps") pcktsz = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(__u32),
+ .value_size = sizeof(__u32),
+ .max_entries = 1,
+};
+
struct bpf_map_def SEC("maps") icmpcnt = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(__u32),
@@ -64,7 +71,8 @@ static __always_inline void ipv4_csum(void *data_start, int data_size,
*csum = csum_fold_helper(*csum);
}
-static __always_inline int send_icmp4_too_big(struct xdp_md *xdp)
+static __always_inline int send_icmp4_too_big(struct xdp_md *xdp,
+ __u32 max_pckt_size)
{
int headroom = (int)sizeof(struct iphdr) + (int)sizeof(struct icmphdr);
@@ -92,7 +100,7 @@ static __always_inline int send_icmp4_too_big(struct xdp_md *xdp)
orig_iph = data + off;
icmp_hdr->type = ICMP_DEST_UNREACH;
icmp_hdr->code = ICMP_FRAG_NEEDED;
- icmp_hdr->un.frag.mtu = htons(MAX_PCKT_SIZE-sizeof(struct ethhdr));
+ icmp_hdr->un.frag.mtu = htons(max_pckt_size - sizeof(struct ethhdr));
icmp_hdr->checksum = 0;
ipv4_csum(icmp_hdr, ICMP_TOOBIG_PAYLOAD_SIZE, &csum);
icmp_hdr->checksum = csum;
@@ -118,14 +126,21 @@ static __always_inline int handle_ipv4(struct xdp_md *xdp)
{
void *data_end = (void *)(long)xdp->data_end;
void *data = (void *)(long)xdp->data;
+ __u32 max_pckt_size = MAX_PCKT_SIZE;
+ __u32 *pckt_sz;
+ __u32 key = 0;
int pckt_size = data_end - data;
int offset;
- if (pckt_size > MAX_PCKT_SIZE) {
+ pckt_sz = bpf_map_lookup_elem(&pcktsz, &key);
+ if (pckt_sz && *pckt_sz)
+ max_pckt_size = *pckt_sz;
+
+ if (pckt_size > max_pckt_size) {
offset = pckt_size - ICMP_TOOBIG_SIZE;
if (bpf_xdp_adjust_tail(xdp, 0 - offset))
return XDP_PASS;
- return send_icmp4_too_big(xdp);
+ return send_icmp4_too_big(xdp, max_pckt_size);
}
return XDP_PASS;
}
diff --git a/samples/bpf/xdp_adjust_tail_user.c b/samples/bpf/xdp_adjust_tail_user.c
index a3596b617c4c..29ade7caf841 100644
--- a/samples/bpf/xdp_adjust_tail_user.c
+++ b/samples/bpf/xdp_adjust_tail_user.c
@@ -72,6 +72,7 @@ static void usage(const char *cmd)
printf("Usage: %s [...]\n", cmd);
printf(" -i <ifname|ifindex> Interface\n");
printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n");
+ printf(" -P <MAX_PCKT_SIZE> Default: 600\n");
printf(" -S use skb-mode\n");
printf(" -N enforce native mode\n");
printf(" -F force loading prog\n");
@@ -85,13 +86,14 @@ int main(int argc, char **argv)
.prog_type = BPF_PROG_TYPE_XDP,
};
unsigned char opt_flags[256] = {};
- const char *optstr = "i:T:SNFh";
+ const char *optstr = "i:T:P:SNFh";
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
+ __u32 max_pckt_size = 0;
+ __u32 key = 0;
unsigned int kill_after_s = 0;
int i, prog_fd, map_fd, opt;
struct bpf_object *obj;
- struct bpf_map *map;
char filename[256];
int err;
@@ -110,6 +112,9 @@ int main(int argc, char **argv)
case 'T':
kill_after_s = atoi(optarg);
break;
+ case 'P':
+ max_pckt_size = atoi(optarg);
+ break;
case 'S':
xdp_flags |= XDP_FLAGS_SKB_MODE;
break;
@@ -150,12 +155,22 @@ int main(int argc, char **argv)
if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
return 1;
- map = bpf_map__next(NULL, obj);
- if (!map) {
- printf("finding a map in obj file failed\n");
+ /* update pcktsz map */
+ if (max_pckt_size) {
+ map_fd = bpf_object__find_map_fd_by_name(obj, "pcktsz");
+ if (!map_fd) {
+ printf("finding a pcktsz map in obj file failed\n");
+ return 1;
+ }
+ bpf_map_update_elem(map_fd, &key, &max_pckt_size, BPF_ANY);
+ }
+
+ /* fetch icmpcnt map */
+ map_fd = bpf_object__find_map_fd_by_name(obj, "icmpcnt");
+ if (!map_fd) {
+ printf("finding a icmpcnt map in obj file failed\n");
return 1;
}
- map_fd = bpf_map__fd(map);
if (!prog_fd) {
printf("load_bpf_file: %s\n", strerror(errno));
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [bpf-next, v2] samples: bpf: add max_pckt_size option at xdp_adjust_tail
2019-08-26 16:25 [bpf-next, v2] samples: bpf: add max_pckt_size option at xdp_adjust_tail Daniel T. Lee
@ 2019-08-29 20:41 ` Song Liu
2019-08-29 18:23 ` Daniel T. Lee
0 siblings, 1 reply; 4+ messages in thread
From: Song Liu @ 2019-08-29 20:41 UTC (permalink / raw)
To: Daniel T. Lee; +Cc: Daniel Borkmann, Alexei Starovoitov, Networking
On Mon, Aug 26, 2019 at 9:52 AM Daniel T. Lee <danieltimlee@gmail.com> wrote:
>
> Currently, at xdp_adjust_tail_kern.c, MAX_PCKT_SIZE is limited
> to 600. To make this size flexible, a new map 'pcktsz' is added.
>
> By updating new packet size to this map from the userland,
> xdp_adjust_tail_kern.o will use this value as a new max_pckt_size.
>
> If no '-P <MAX_PCKT_SIZE>' option is used, the size of maximum packet
> will be 600 as a default.
Please also cc bpf@vger.kernel.org for bpf patches.
>
> Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
With a nit below.
[...]
> diff --git a/samples/bpf/xdp_adjust_tail_user.c b/samples/bpf/xdp_adjust_tail_user.c
> index a3596b617c4c..29ade7caf841 100644
> --- a/samples/bpf/xdp_adjust_tail_user.c
> +++ b/samples/bpf/xdp_adjust_tail_user.c
> @@ -72,6 +72,7 @@ static void usage(const char *cmd)
> printf("Usage: %s [...]\n", cmd);
> printf(" -i <ifname|ifindex> Interface\n");
> printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n");
> + printf(" -P <MAX_PCKT_SIZE> Default: 600\n");
nit: printf(" -P <MAX_PCKT_SIZE> Default: %u\n", MAX_PCKT_SIZE);
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [bpf-next, v2] samples: bpf: add max_pckt_size option at xdp_adjust_tail
2019-08-29 20:41 ` Song Liu
@ 2019-08-29 18:23 ` Daniel T. Lee
2019-09-02 4:43 ` Daniel T. Lee
0 siblings, 1 reply; 4+ messages in thread
From: Daniel T. Lee @ 2019-08-29 18:23 UTC (permalink / raw)
To: Song Liu; +Cc: Daniel Borkmann, Alexei Starovoitov, Networking
On Fri, Aug 30, 2019 at 5:42 AM Song Liu <liu.song.a23@gmail.com> wrote:
>
> On Mon, Aug 26, 2019 at 9:52 AM Daniel T. Lee <danieltimlee@gmail.com> wrote:
> >
> > Currently, at xdp_adjust_tail_kern.c, MAX_PCKT_SIZE is limited
> > to 600. To make this size flexible, a new map 'pcktsz' is added.
> >
> > By updating new packet size to this map from the userland,
> > xdp_adjust_tail_kern.o will use this value as a new max_pckt_size.
> >
> > If no '-P <MAX_PCKT_SIZE>' option is used, the size of maximum packet
> > will be 600 as a default.
>
> Please also cc bpf@vger.kernel.org for bpf patches.
>
I'll make sure to have it included next time.
> >
> > Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
>
> Acked-by: Song Liu <songliubraving@fb.com>
>
> With a nit below.
>
> [...]
>
> > diff --git a/samples/bpf/xdp_adjust_tail_user.c b/samples/bpf/xdp_adjust_tail_user.c
> > index a3596b617c4c..29ade7caf841 100644
> > --- a/samples/bpf/xdp_adjust_tail_user.c
> > +++ b/samples/bpf/xdp_adjust_tail_user.c
> > @@ -72,6 +72,7 @@ static void usage(const char *cmd)
> > printf("Usage: %s [...]\n", cmd);
> > printf(" -i <ifname|ifindex> Interface\n");
> > printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n");
> > + printf(" -P <MAX_PCKT_SIZE> Default: 600\n");
>
> nit: printf(" -P <MAX_PCKT_SIZE> Default: %u\n", MAX_PCKT_SIZE);
With all due respect, I'm afraid that MAX_PCKT_SIZE constant is only
defined at '_kern.c'.
Are you saying that it should be defined at '_user.c' either?
Thanks for the review!
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [bpf-next, v2] samples: bpf: add max_pckt_size option at xdp_adjust_tail
2019-08-29 18:23 ` Daniel T. Lee
@ 2019-09-02 4:43 ` Daniel T. Lee
0 siblings, 0 replies; 4+ messages in thread
From: Daniel T. Lee @ 2019-09-02 4:43 UTC (permalink / raw)
To: Song Liu; +Cc: Daniel Borkmann, Alexei Starovoitov, Networking
On Fri, Aug 30, 2019 at 3:23 AM Daniel T. Lee <danieltimlee@gmail.com> wrote:
>
> On Fri, Aug 30, 2019 at 5:42 AM Song Liu <liu.song.a23@gmail.com> wrote:
> >
> > On Mon, Aug 26, 2019 at 9:52 AM Daniel T. Lee <danieltimlee@gmail.com> wrote:
> > >
> > > Currently, at xdp_adjust_tail_kern.c, MAX_PCKT_SIZE is limited
> > > to 600. To make this size flexible, a new map 'pcktsz' is added.
> > >
> > > By updating new packet size to this map from the userland,
> > > xdp_adjust_tail_kern.o will use this value as a new max_pckt_size.
> > >
> > > If no '-P <MAX_PCKT_SIZE>' option is used, the size of maximum packet
> > > will be 600 as a default.
> >
> > Please also cc bpf@vger.kernel.org for bpf patches.
> >
>
> I'll make sure to have it included next time.
>
> > >
> > > Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
> >
> > Acked-by: Song Liu <songliubraving@fb.com>
> >
> > With a nit below.
> >
> > [...]
> >
> > > diff --git a/samples/bpf/xdp_adjust_tail_user.c b/samples/bpf/xdp_adjust_tail_user.c
> > > index a3596b617c4c..29ade7caf841 100644
> > > --- a/samples/bpf/xdp_adjust_tail_user.c
> > > +++ b/samples/bpf/xdp_adjust_tail_user.c
> > > @@ -72,6 +72,7 @@ static void usage(const char *cmd)
> > > printf("Usage: %s [...]\n", cmd);
> > > printf(" -i <ifname|ifindex> Interface\n");
> > > printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n");
> > > + printf(" -P <MAX_PCKT_SIZE> Default: 600\n");
> >
> > nit: printf(" -P <MAX_PCKT_SIZE> Default: %u\n", MAX_PCKT_SIZE);
>
> With all due respect, I'm afraid that MAX_PCKT_SIZE constant is only
> defined at '_kern.c'.
> Are you saying that it should be defined at '_user.c' either?
>
> Thanks for the review!
Ping?
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-08-26 16:25 [bpf-next, v2] samples: bpf: add max_pckt_size option at xdp_adjust_tail Daniel T. Lee
2019-08-29 20:41 ` Song Liu
2019-08-29 18:23 ` Daniel T. Lee
2019-09-02 4:43 ` Daniel T. Lee
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