S_TCPOPT_SND_WSCALE
#define V_TCPOPT_SND_WSCALE(x) ((x) << S_TCPOPT_SND_WSCALE)
#define G_TCPOPT_SND_WSCALE(x) (((x) >> S_TCPOPT_SND_WSCALE) & M_TCPOPT_SND_WSCALE)