On Fri, Sep 20, 2024 at 11:56:31AM +0200, Laurent Vivier wrote:
> As tcp_update_check_tcp4() and tcp_update_check_tcp6() compute the
> checksum using the TCP header and the TCP payload, it is clearer
> to use a pointer to tcp_payload_t that includes tcphdr and payload
> rather than a pointer to tcphdr (and guessing TCP header is
> followed by the payload).
> 
> Move tcp_payload_t and tcp_flags_t to tcp_internal.h.
> (They will be used also by vhost-user).
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

Of course, it will conflict with Jon's pending changes merging the
payload and flags arrays.

> ---
>  tcp.c          | 42 ++++++++++++++++++++++--------------------
>  tcp_buf.c      | 29 -----------------------------
>  tcp_internal.h | 29 +++++++++++++++++++++++++++++
>  3 files changed, 51 insertions(+), 49 deletions(-)
> 
> diff --git a/tcp.c b/tcp.c
> index 1962fcc469ed..c9472d905520 100644
> --- a/tcp.c
> +++ b/tcp.c
> @@ -757,32 +757,34 @@ static void tcp_sock_set_bufsize(const struct ctx *c, int s)
>  /**
>   * tcp_update_check_tcp4() - Update TCP checksum from stored one
>   * @iph:	IPv4 header
> - * @th:		TCP header followed by TCP payload
> + * @bp:		TCP header followed by TCP payload
>   */
> -static void tcp_update_check_tcp4(const struct iphdr *iph, struct tcphdr *th)
> +static void tcp_update_check_tcp4(const struct iphdr *iph,
> +				  struct tcp_payload_t *bp)
>  {
>  	uint16_t l4len = ntohs(iph->tot_len) - sizeof(struct iphdr);
>  	struct in_addr saddr = { .s_addr = iph->saddr };
>  	struct in_addr daddr = { .s_addr = iph->daddr };
>  	uint32_t sum = proto_ipv4_header_psum(l4len, IPPROTO_TCP, saddr, daddr);
>  
> -	th->check = 0;
> -	th->check = csum(th, l4len, sum);
> +	bp->th.check = 0;
> +	bp->th.check = csum(bp, l4len, sum);
>  }
>  
>  /**
>   * tcp_update_check_tcp6() - Calculate TCP checksum for IPv6
>   * @ip6h:	IPv6 header
> - * @th:		TCP header followed by TCP payload
> + * @bp:		TCP header followed by TCP payload
>   */
> -static void tcp_update_check_tcp6(struct ipv6hdr *ip6h, struct tcphdr *th)
> +static void tcp_update_check_tcp6(const struct ipv6hdr *ip6h,
> +				  struct tcp_payload_t *bp)
>  {
>  	uint16_t l4len = ntohs(ip6h->payload_len);
>  	uint32_t sum = proto_ipv6_header_psum(l4len, IPPROTO_TCP,
>  					      &ip6h->saddr, &ip6h->daddr);
>  
> -	th->check = 0;
> -	th->check = csum(th, l4len, sum);
> +	bp->th.check = 0;
> +	bp->th.check = csum(bp, l4len, sum);
>  }
>  
>  /**
> @@ -902,7 +904,7 @@ static void tcp_fill_header(struct tcphdr *th,
>   * @conn:		Connection pointer
>   * @taph:		tap backend specific header
>   * @iph:		Pointer to IPv4 header
> - * @th:			Pointer to TCP header
> + * @bp:			Pointer to TCP header followed by TCP payload
>   * @dlen:		TCP payload length
>   * @check:		Checksum, if already known
>   * @seq:		Sequence number for this segment
> @@ -912,14 +914,14 @@ static void tcp_fill_header(struct tcphdr *th,
>   */
>  static size_t tcp_fill_headers4(const struct tcp_tap_conn *conn,
>  				struct tap_hdr *taph,
> -				struct iphdr *iph, struct tcphdr *th,
> +				struct iphdr *iph, struct tcp_payload_t *bp,
>  				size_t dlen, const uint16_t *check,
>  				uint32_t seq, bool no_tcp_csum)
>  {
>  	const struct flowside *tapside = TAPFLOW(conn);
>  	const struct in_addr *src4 = inany_v4(&tapside->oaddr);
>  	const struct in_addr *dst4 = inany_v4(&tapside->eaddr);
> -	size_t l4len = dlen + sizeof(*th);
> +	size_t l4len = dlen + sizeof(bp->th);
>  	size_t l3len = l4len + sizeof(*iph);
>  
>  	ASSERT(src4 && dst4);
> @@ -931,12 +933,12 @@ static size_t tcp_fill_headers4(const struct tcp_tap_conn *conn,
>  	iph->check = check ? *check :
>  			     csum_ip4_header(l3len, IPPROTO_TCP, *src4, *dst4);
>  
> -	tcp_fill_header(th, conn, seq);
> +	tcp_fill_header(&bp->th, conn, seq);
>  
>  	if (no_tcp_csum)
> -		th->check = 0;
> +		bp->th.check = 0;
>  	else
> -		tcp_update_check_tcp4(iph, th);
> +		tcp_update_check_tcp4(iph, bp);
>  
>  	tap_hdr_update(taph, l3len + sizeof(struct ethhdr));
>  
> @@ -948,7 +950,7 @@ static size_t tcp_fill_headers4(const struct tcp_tap_conn *conn,
>   * @conn:		Connection pointer
>   * @taph:		tap backend specific header
>   * @ip6h:		Pointer to IPv6 header
> - * @th:			Pointer to TCP header
> + * @bp:			Pointer to TCP header followed by TCP payload
>   * @dlen:		TCP payload length
>   * @check:		Checksum, if already known
>   * @seq:		Sequence number for this segment
> @@ -958,11 +960,11 @@ static size_t tcp_fill_headers4(const struct tcp_tap_conn *conn,
>   */
>  static size_t tcp_fill_headers6(const struct tcp_tap_conn *conn,
>  				struct tap_hdr *taph,
> -				struct ipv6hdr *ip6h, struct tcphdr *th,
> +				struct ipv6hdr *ip6h, struct tcp_payload_t *bp,
>  				size_t dlen, uint32_t seq, bool no_tcp_csum)
>  {
>  	const struct flowside *tapside = TAPFLOW(conn);
> -	size_t l4len = dlen + sizeof(*th);
> +	size_t l4len = dlen + sizeof(bp->th);
>  
>  	ip6h->payload_len = htons(l4len);
>  	ip6h->saddr = tapside->oaddr.a6;
> @@ -976,12 +978,12 @@ static size_t tcp_fill_headers6(const struct tcp_tap_conn *conn,
>  	ip6h->flow_lbl[1] = (conn->sock >> 8) & 0xff;
>  	ip6h->flow_lbl[2] = (conn->sock >> 0) & 0xff;
>  
> -	tcp_fill_header(th, conn, seq);
> +	tcp_fill_header(&bp->th, conn, seq);
>  
>  	if (no_tcp_csum)
> -		th->check = 0;
> +		bp->th.check = 0;
>  	else
> -		tcp_update_check_tcp6(ip6h, th);
> +		tcp_update_check_tcp6(ip6h, bp);
>  
>  	tap_hdr_update(taph, l4len + sizeof(*ip6h) + sizeof(struct ethhdr));
>  
> diff --git a/tcp_buf.c b/tcp_buf.c
> index ffbff5e4b485..238827b01d90 100644
> --- a/tcp_buf.c
> +++ b/tcp_buf.c
> @@ -38,35 +38,6 @@
>  	(c->mode == MODE_PASTA ? 1 : TCP_FRAMES_MEM)
>  
>  /* Static buffers */
> -/**
> - * struct tcp_payload_t - TCP header and data to send segments with payload
> - * @th:		TCP header
> - * @data:	TCP data
> - */
> -struct tcp_payload_t {
> -	struct tcphdr th;
> -	uint8_t data[IP_MAX_MTU - sizeof(struct tcphdr)];
> -#ifdef __AVX2__
> -} __attribute__ ((packed, aligned(32)));    /* For AVX2 checksum routines */
> -#else
> -} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
> -#endif
> -
> -/**
> - * struct tcp_flags_t - TCP header and data to send zero-length
> - *                      segments (flags)
> - * @th:		TCP header
> - * @opts	TCP options
> - */
> -struct tcp_flags_t {
> -	struct tcphdr th;
> -	char opts[OPT_MSS_LEN + OPT_WS_LEN + 1];
> -#ifdef __AVX2__
> -} __attribute__ ((packed, aligned(32)));
> -#else
> -} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
> -#endif
> -
>  /* Ethernet header for IPv4 frames */
>  static struct ethhdr		tcp4_eth_src;
>  
> diff --git a/tcp_internal.h b/tcp_internal.h
> index de06db1438d6..2f74ffeff8f3 100644
> --- a/tcp_internal.h
> +++ b/tcp_internal.h
> @@ -63,6 +63,35 @@ enum tcp_iov_parts {
>  	TCP_NUM_IOVS
>  };
>  
> +/**
> + * struct tcp_payload_t - TCP header and data to send segments with payload
> + * @th:		TCP header
> + * @data:	TCP data
> + */
> +struct tcp_payload_t {
> +	struct tcphdr th;
> +	uint8_t data[IP_MAX_MTU - sizeof(struct tcphdr)];
> +#ifdef __AVX2__
> +} __attribute__ ((packed, aligned(32)));    /* For AVX2 checksum routines */
> +#else
> +} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
> +#endif
> +
> +/**
> + * struct tcp_flags_t - TCP header and data to send zero-length
> + *                      segments (flags)
> + * @th:		TCP header
> + * @opts	TCP options
> + */
> +struct tcp_flags_t {
> +	struct tcphdr th;
> +	char opts[OPT_MSS_LEN + OPT_WS_LEN + 1];
> +#ifdef __AVX2__
> +} __attribute__ ((packed, aligned(32)));
> +#else
> +} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
> +#endif
> +
>  extern char tcp_buf_discard [MAX_WINDOW];
>  
>  void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn,

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson