From: David Gibson <david@gibson.dropbear.id.au>
To: Laurent Vivier <lvivier@redhat.com>
Cc: passt-dev@passt.top
Subject: Re: [PATCH] tcp: Use tcp_payload_t rather than tcphdr
Date: Mon, 23 Sep 2024 13:43:55 +1000 [thread overview]
Message-ID: <ZvDj-0iZSvELAB3P@zatzit.fritz.box> (raw)
In-Reply-To: <20240920095631.3911625-1-lvivier@redhat.com>
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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
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prev parent reply other threads:[~2024-09-23 3:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-20 9:56 [PATCH] tcp: Use tcp_payload_t rather than tcphdr Laurent Vivier
2024-09-23 3:43 ` David Gibson [this message]
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