ensure ipv6_data_t alignment

tools/tcpdrop.py

@@ -53,7 +53,6 @@
 // separate data structs for ipv4 and ipv6
 struct ipv4_data_t {
  // XXX: switch some to u32's when supported
- u64 stack_id;
  u64 pid;
  u64 ip;
  u64 saddr;
@@ -62,11 +61,11 @@
  u64 dport;
  u64 state;
  u64 tcpflags;
+ u64 stack_id;
 };
 BPF_PERF_OUTPUT(ipv4_events);
 
 struct ipv6_data_t {
- u64 stack_id;
  u64 pid;
  u64 ip;
  unsigned __int128 saddr;
@@ -75,6 +74,7 @@
  u64 dport;
  u64 state;
  u64 tcpflags;
+ u64 stack_id;
 };
 BPF_PERF_OUTPUT(ipv6_events);
 
@@ -120,8 +120,8 @@
  bpf_probe_read(&data4.daddr, sizeof(u32), &ip->daddr);
  data4.dport = dport;
  data4.sport = sport;
- data4.tcpflags = tcpflags;
  data4.state = state;
+ data4.tcpflags = tcpflags;
  data4.stack_id = stack_traces.get_stackid(ctx, 0);
  ipv4_events.perf_submit(ctx, &data4, sizeof(data4));
 
@@ -133,8 +133,8 @@
  sk->__sk_common.skc_v6_daddr.in6_u.u6_addr32);
  data6.dport = dport;
  data6.sport = sport;
- data6.tcpflags = tcpflags;
  data6.state = state;
+ data6.tcpflags = tcpflags;
  data6.stack_id = stack_traces.get_stackid(ctx, 0);
  ipv6_events.perf_submit(ctx, &data6, sizeof(data6));
  }
@@ -152,28 +152,28 @@
 # event data
 class Data_ipv4(ct.Structure):
  _fields_ = [
- ("stack_id", ct.c_ulonglong),
  ("pid", ct.c_ulonglong),
  ("ip", ct.c_ulonglong),
  ("saddr", ct.c_ulonglong),
  ("daddr", ct.c_ulonglong),
  ("sport", ct.c_ulonglong),
  ("dport", ct.c_ulonglong),
  ("state", ct.c_ulonglong),
- ("tcpflags", ct.c_ulonglong)
+ ("tcpflags", ct.c_ulonglong),
+ ("stack_id", ct.c_ulonglong)
  ]
 
 class Data_ipv6(ct.Structure):
  _fields_ = [
- ("stack_id", ct.c_ulonglong),
  ("pid", ct.c_ulonglong),
  ("ip", ct.c_ulonglong),
  ("saddr", (ct.c_ulonglong * 2)),
  ("daddr", (ct.c_ulonglong * 2)),
  ("sport", ct.c_ulonglong),
  ("dport", ct.c_ulonglong),
  ("state", ct.c_ulonglong),
- ("tcpflags", ct.c_ulonglong)
+ ("tcpflags", ct.c_ulonglong),
+ ("stack_id", ct.c_ulonglong)
  ]
 
 # process event