G_TCPOPT_SND_WSCALE
#define G_TCPOPT_SND_WSCALE(x) (((x) >> 8) & 0xf)
#define G_TCPOPT_SND_WSCALE(x) (((x) >> S_TCPOPT_SND_WSCALE) & M_TCPOPT_SND_WSCALE)