136 	/* Needed to calculate csum and parse TCP options. */  in tcp_reload_headers()
161 static __sum16 tcp_v4_csum(struct tcp_syncookie *ctx, __wsum csum)  in tcp_v4_csum()  argument
164 				 ctx->tcp->doff * 4, IPPROTO_TCP, csum);  in tcp_v4_csum()
167 static __sum16 tcp_v6_csum(struct tcp_syncookie *ctx, __wsum csum)  in tcp_v6_csum()  argument
170 			       ctx->tcp->doff * 4, IPPROTO_TCP, csum);  in tcp_v6_csum()
175 	s64 csum;  in tcp_validate_header()  local
180 	csum = bpf_csum_diff(0, 0, (void *)ctx->tcp, ctx->tcp->doff * 4, 0);  in tcp_validate_header()
181 	if (csum < 0)  in tcp_validate_header()
185 		/* check tcp_v4_csum(csum) is 0 if not on lo. */  in tcp_validate_header()
187 		csum = bpf_csum_diff(0, 0, (void *)ctx->ipv4, ctx->ipv4->ihl * 4, 0);  in tcp_validate_header()
188 		if (csum < 0)  in tcp_validate_header()
191 		if (csum_fold(csum) != 0)  in tcp_validate_header()
194 		/* check tcp_v6_csum(csum) is 0 if not on lo. */  in tcp_validate_header()
401 	s64 csum;  in tcp_handle_syn()  local
424 	csum = bpf_csum_diff(0, 0, (void *)ctx->tcp, ctx->tcp->doff * 4, 0);  in tcp_handle_syn()
425 	if (csum < 0)  in tcp_handle_syn()
430 		ctx->tcp->check = tcp_v4_csum(ctx, csum);  in tcp_handle_syn()
438 		csum = bpf_csum_diff(0, 0, (void *)ctx->ipv4, sizeof(*ctx->ipv4), 0);  in tcp_handle_syn()
439 		if (csum < 0)  in tcp_handle_syn()
442 		ctx->ipv4->check = csum_fold(csum);  in tcp_handle_syn()
445 		ctx->tcp->check = tcp_v6_csum(ctx, csum);  in tcp_handle_syn()