This patchset is to handle the txstamp-ack bit when
fragmenting/coalescing skbs.
The second patch depends on the recently posted series
for the net branch:
"tcp: Merge timestamp info when coalescing skbs"
A BPF prog is used to kprobe to sock_queue_err_skb()
and print out the value of serr->ee.ee_data. The BPF
prog (run-able from bcc) is attached here:
BPF prog used for testing:
~~~~~
#!/usr/bin/env python
from __future__ import print_function
from bcc import BPF
bpf_text = """
#include <uapi/linux/ptrace.h>
#include <net/sock.h>
#include <bcc/proto.h>
#include <linux/errqueue.h>
#ifdef memset
#undef memset
#endif
int trace_err_skb(struct pt_regs *ctx)
{
struct sk_buff *skb = (struct sk_buff *)ctx->si;
struct sock *sk = (struct sock *)ctx->di;
struct sock_exterr_skb *serr;
u32 ee_data = 0;
if (!sk || !skb)
return 0;
serr = SKB_EXT_ERR(skb);
bpf_probe_read(&ee_data, sizeof(ee_data), &serr->ee.ee_data);
bpf_trace_printk("ee_data:%u\\n", ee_data);
return 0;
};
"""
b = BPF(text=bpf_text)
b.attach_kprobe(event="sock_queue_err_skb", fn_name="trace_err_skb")
print("Attached to kprobe")
b.trace_print()
