BPF_ALIGNMENT
p->sf.base = malloc(p->bufsize + BPF_ALIGNMENT);
p->buffer = p->sf.base + BPF_ALIGNMENT - (linklen % BPF_ALIGNMENT);
#define BPF_WORDALIGN(x) (((x) + (BPF_ALIGNMENT - 1)) & ~(BPF_ALIGNMENT - 1))
p->sf.base = malloc(p->bufsize + BPF_ALIGNMENT);
p->buffer = p->sf.base + BPF_ALIGNMENT - (linklen % BPF_ALIGNMENT);