int val = TPACKET_V2;
CHECK(setsockopt(s, SOL_PACKET, PACKET_VERSION, &val, sizeof(val)));
socklen_t len = sizeof(ctx->hdrlen);
int val = TPACKET_V2;
CHECK(setsockopt(s, SOL_PACKET, PACKET_VERSION, &val, sizeof(val)));
socklen_t len = sizeof(ctx->hdrlen);