From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gandalf.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by passt.top (Postfix) with ESMTPS id 81E7C5A0271 for ; Mon, 4 Mar 2024 01:55:02 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202312; t=1709513695; bh=LWgtCfcnL66vWBq8+5tSCjYkRMEhgn2pK0Dgp8lLNjo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ObZKp7PvQxMctlnMX/7rwbahcOllGBcEJaoUQALbu46rjpJediZvn8WBEGuyJr38M QCium1Vz9S03mam7SusFoncz9vX+5rKjD5c1gFHLo+6eXhyi4JTQGuK5/tDDY6pGS2 jSUoDxdMIxW9Ndh+M9Qb+qocfVmkbZKFtlXbjk6ne1D2OYCr3opxV3yQhYd9lYmcil MTr1ox/FAiEc1K63UAJEUCo/NV1hgq+QtsVWa/N62lfyTSmDnZY+J0QsYkc2n1+6Jz dgzATACDxNijqpcLmBxXAUHxZU0Lpl+618Tcg5V7bomYvS8dbezsCKwpW23tloUbbw eYOO6oK6lEa8g== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4Tp0bM6sw4z4wcJ; Mon, 4 Mar 2024 11:54:55 +1100 (AEDT) Date: Mon, 4 Mar 2024 11:52:31 +1100 From: David Gibson To: Laurent Vivier Subject: Re: [PATCH v5 7/9] checksum: introduce functions to compute the header part checksum for TCP/UDP Message-ID: References: <20240303135114.1023026-1-lvivier@redhat.com> <20240303135114.1023026-8-lvivier@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="FTW1+uVO8CBVuS6k" Content-Disposition: inline In-Reply-To: <20240303135114.1023026-8-lvivier@redhat.com> Message-ID-Hash: KSUBN426GACOR27BMKNXW3375KN6HXIL X-Message-ID-Hash: KSUBN426GACOR27BMKNXW3375KN6HXIL X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: passt-dev@passt.top X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --FTW1+uVO8CBVuS6k Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Mar 03, 2024 at 02:51:12PM +0100, Laurent Vivier wrote: > The TCP and UDP checksums are computed using the data in the TCP/UDP > payload but also some informations in the IP header (protocol, > length, source and destination addresses). >=20 > We add two functions, proto_ipv4_header_psum() and > proto_ipv6_header_psum(), to compute the checksum of the IP > header part. >=20 > Signed-off-by: Laurent Vivier Reviewed-by: David Gibson > --- >=20 > Notes: > v5: > - use struct in_addr > - update tcp_update_check_tcp4()/tcp_update_check_tcp6() > function comment and add tcphdr as a parameter > =20 > v4: > - fix payload length endianness > =20 > v3: > - function parameters provide tot_len, saddr, daddr and protocol > rather than an iphdr/ipv6hdr > =20 > v2: > - move new function to checksum.c > - use _psum rather than _checksum in the name > - replace csum_udp4() and csum_udp6() by the new function > =20 > v5: > - use struct in_addr > =20 > v4: > - fix payload length endianness > =20 > v3: > - function parameters provide tot_len, saddr, daddr and protocol > rather than an iphdr/ipv6hdr > =20 > v2: > - move new function to checksum.c > - use _psum rather than _checksum in the name > - replace csum_udp4() and csum_udp6() by the new function >=20 > checksum.c | 67 ++++++++++++++++++++++++++++++++++++++++++------------ > checksum.h | 5 ++++ > tcp.c | 50 +++++++++++++++++++--------------------- > udp.c | 18 ++++++++------- > 4 files changed, 90 insertions(+), 50 deletions(-) >=20 > diff --git a/checksum.c b/checksum.c > index ad81a7104a07..7625d7a41303 100644 > --- a/checksum.c > +++ b/checksum.c > @@ -139,6 +139,29 @@ uint16_t csum_ip4_header(uint16_t tot_len, uint8_t p= rotocol, > return ~csum_fold(sum); > } > =20 > +/** > + * proto_ipv4_header_psum() - Calculates the partial checksum of an > + * IPv4 header for UDP or TCP > + * @tot_len: IPv4 Payload length (host order) > + * @proto: Protocol number (host order) "host order" is meaningless here, because it's a single byte value. That can be fixed in followup though. > + * @saddr: Source address (network order) > + * @daddr: Destination address (network order) > + * Returns: Partial checksum of the IPv4 header > + */ > +uint32_t proto_ipv4_header_psum(uint16_t tot_len, uint8_t protocol, > + struct in_addr saddr, struct in_addr daddr) > +{ > + uint32_t psum =3D htons(protocol); > + > + psum +=3D (saddr.s_addr >> 16) & 0xffff; > + psum +=3D saddr.s_addr & 0xffff; > + psum +=3D (daddr.s_addr >> 16) & 0xffff; > + psum +=3D daddr.s_addr & 0xffff; > + psum +=3D htons(tot_len); > + > + return psum; > +} > + > /** > * csum_udp4() - Calculate and set checksum for a UDP over IPv4 packet > * @udp4hr: UDP header, initialised apart from checksum > @@ -155,14 +178,10 @@ void csum_udp4(struct udphdr *udp4hr, > udp4hr->check =3D 0; > =20 > if (UDP4_REAL_CHECKSUMS) { > - /* UNTESTED: if we did want real UDPv4 checksums, this > - * is roughly what we'd need */ > - uint32_t psum =3D csum_fold(saddr.s_addr) > - + csum_fold(daddr.s_addr) > - + htons(len + sizeof(*udp4hr)) > - + htons(IPPROTO_UDP); > - /* Add in partial checksum for the UDP header alone */ > - psum +=3D sum_16b(udp4hr, sizeof(*udp4hr)); > + uint16_t tot_len =3D len + sizeof(struct udphdr); > + uint32_t psum =3D proto_ipv4_header_psum(tot_len, IPPROTO_UDP, > + saddr, daddr); > + psum =3D csum_unfolded(udp4hr, sizeof(struct udphdr), psum); > udp4hr->check =3D csum(payload, len, psum); > } > } > @@ -185,6 +204,27 @@ void csum_icmp4(struct icmphdr *icmp4hr, const void = *payload, size_t len) > icmp4hr->checksum =3D csum(payload, len, psum); > } > =20 > +/** > + * proto_ipv6_header_psum() - Calculates the partial checksum of an > + * IPv6 header for UDP or TCP > + * @payload_len: IPv6 payload length (host order) > + * @proto: Protocol number (host order) > + * @saddr: Source address (network order) > + * @daddr: Destination address (network order) > + * Returns: Partial checksum of the IPv6 header > + */ > +uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol, > + const struct in6_addr *saddr, > + const struct in6_addr *daddr) > +{ > + uint32_t sum =3D htons(protocol) + htons(payload_len); > + > + sum +=3D sum_16b(saddr, sizeof(*saddr)); > + sum +=3D sum_16b(daddr, sizeof(*daddr)); > + > + return sum; > +} > + > /** > * csum_udp6() - Calculate and set checksum for a UDP over IPv6 packet > * @udp6hr: UDP header, initialised apart from checksum > @@ -195,14 +235,11 @@ void csum_udp6(struct udphdr *udp6hr, > const struct in6_addr *saddr, const struct in6_addr *daddr, > const void *payload, size_t len) > { > - /* Partial checksum for the pseudo-IPv6 header */ > - uint32_t psum =3D sum_16b(saddr, sizeof(*saddr)) + > - sum_16b(daddr, sizeof(*daddr)) + > - htons(len + sizeof(*udp6hr)) + htons(IPPROTO_UDP); > - > + uint32_t psum =3D proto_ipv6_header_psum(len + sizeof(struct udphdr), > + IPPROTO_UDP, saddr, daddr); > udp6hr->check =3D 0; > - /* Add in partial checksum for the UDP header alone */ > - psum +=3D sum_16b(udp6hr, sizeof(*udp6hr)); > + > + psum =3D csum_unfolded(udp6hr, sizeof(struct udphdr), psum); > udp6hr->check =3D csum(payload, len, psum); > } > =20 > diff --git a/checksum.h b/checksum.h > index e990fefa7f39..d4e563c85f4f 100644 > --- a/checksum.h > +++ b/checksum.h > @@ -15,10 +15,15 @@ uint16_t csum_fold(uint32_t sum); > uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init); > uint16_t csum_ip4_header(uint16_t tot_len, uint8_t protocol, > struct in_addr saddr, struct in_addr daddr); > +uint32_t proto_ipv4_header_psum(uint16_t tot_len, uint8_t protocol, > + struct in_addr saddr, struct in_addr daddr); > void csum_udp4(struct udphdr *udp4hr, > struct in_addr saddr, struct in_addr daddr, > const void *payload, size_t len); > void csum_icmp4(struct icmphdr *ih, const void *payload, size_t len); > +uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol, > + const struct in6_addr *saddr, > + const struct in6_addr *daddr); > void csum_udp6(struct udphdr *udp6hr, > const struct in6_addr *saddr, const struct in6_addr *daddr, > const void *payload, size_t len); > diff --git a/tcp.c b/tcp.c > index 7fb9dba95a6a..53da8b84780f 100644 > --- a/tcp.c > +++ b/tcp.c > @@ -937,41 +937,33 @@ static void tcp_sock_set_bufsize(const struct ctx *= c, int s) > =20 > /** > * tcp_update_check_tcp4() - Update TCP checksum from stored one > - * @buf: L2 packet buffer with final IPv4 header > + * @iph: IPv4 header > + * @th: TCP header followed by TCP payload > */ > -static void tcp_update_check_tcp4(struct tcp4_l2_buf_t *buf) > +static void tcp_update_check_tcp4(struct iphdr *iph, struct tcphdr *th) > { > - uint16_t tlen =3D ntohs(buf->iph.tot_len) - 20; > - uint32_t sum =3D htons(IPPROTO_TCP); > + uint16_t tlen =3D ntohs(iph->tot_len) - sizeof(struct iphdr); > + uint32_t sum =3D proto_ipv4_header_psum(tlen, IPPROTO_TCP, > + (struct in_addr){ .s_addr =3D iph->saddr }, > + (struct in_addr){ .s_addr =3D iph->daddr }); > =20 > - sum +=3D (buf->iph.saddr >> 16) & 0xffff; > - sum +=3D buf->iph.saddr & 0xffff; > - sum +=3D (buf->iph.daddr >> 16) & 0xffff; > - sum +=3D buf->iph.daddr & 0xffff; > - sum +=3D htons(ntohs(buf->iph.tot_len) - 20); > - > - buf->th.check =3D 0; > - buf->th.check =3D csum(&buf->th, tlen, sum); > + th->check =3D 0; > + th->check =3D csum(th, tlen, sum); > } > =20 > /** > * tcp_update_check_tcp6() - Calculate TCP checksum for IPv6 > - * @buf: L2 packet buffer with final IPv6 header > + * @ip6h: IPv6 header > + * @th: TCP header followed by TCP payload > */ > -static void tcp_update_check_tcp6(struct tcp6_l2_buf_t *buf) > +static void tcp_update_check_tcp6(struct ipv6hdr *ip6h, struct tcphdr *t= h) > { > - int len =3D ntohs(buf->ip6h.payload_len) + sizeof(struct ipv6hdr); > - > - buf->ip6h.hop_limit =3D IPPROTO_TCP; > - buf->ip6h.version =3D 0; > - buf->ip6h.nexthdr =3D 0; > + uint16_t payload_len =3D ntohs(ip6h->payload_len); > + uint32_t sum =3D proto_ipv6_header_psum(payload_len, IPPROTO_TCP, > + &ip6h->saddr, &ip6h->daddr); > =20 > - buf->th.check =3D 0; > - buf->th.check =3D csum(&buf->ip6h, len, 0); > - > - buf->ip6h.hop_limit =3D 255; > - buf->ip6h.version =3D 6; > - buf->ip6h.nexthdr =3D IPPROTO_TCP; > + th->check =3D 0; > + th->check =3D csum(th, payload_len, sum); > } > =20 > /** > @@ -1383,7 +1375,7 @@ do { \ > =20 > SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq); > =20 > - tcp_update_check_tcp4(b); > + tcp_update_check_tcp4(&b->iph, &b->th); > =20 > tlen =3D tap_iov_len(c, &b->taph, ip_len); > } else { > @@ -1402,7 +1394,11 @@ do { \ > =20 > SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq); > =20 > - tcp_update_check_tcp6(b); > + tcp_update_check_tcp6(&b->ip6h, &b->th); > + > + b->ip6h.hop_limit =3D 255; > + b->ip6h.version =3D 6; > + b->ip6h.nexthdr =3D IPPROTO_TCP; > =20 > b->ip6h.flow_lbl[0] =3D (conn->sock >> 16) & 0xf; > b->ip6h.flow_lbl[1] =3D (conn->sock >> 8) & 0xff; > diff --git a/udp.c b/udp.c > index fb8373beba40..2fd67925f368 100644 > --- a/udp.c > +++ b/udp.c > @@ -625,6 +625,7 @@ static size_t udp_update_hdr6(const struct ctx *c, in= t n, in_port_t dstport, > { > struct udp6_l2_buf_t *b =3D &udp6_l2_buf[n]; > const struct in6_addr *src, *dst; > + uint16_t payload_len; > in_port_t src_port; > size_t ip_len; > =20 > @@ -634,7 +635,8 @@ static size_t udp_update_hdr6(const struct ctx *c, in= t n, in_port_t dstport, > =20 > ip_len =3D udp6_l2_mh_sock[n].msg_len + sizeof(b->ip6h) + sizeof(b->uh); > =20 > - b->ip6h.payload_len =3D htons(udp6_l2_mh_sock[n].msg_len + sizeof(b->uh= )); > + payload_len =3D udp6_l2_mh_sock[n].msg_len + sizeof(b->uh); > + b->ip6h.payload_len =3D htons(payload_len); > =20 > if (IN6_IS_ADDR_LINKLOCAL(src)) { > dst =3D &c->ip6.addr_ll_seen; > @@ -670,17 +672,17 @@ static size_t udp_update_hdr6(const struct ctx *c, = int n, in_port_t dstport, > } > b->ip6h.daddr =3D *dst; > b->ip6h.saddr =3D *src; > + b->ip6h.version =3D 6; > + b->ip6h.nexthdr =3D IPPROTO_UDP; > + b->ip6h.hop_limit =3D 255; > =20 > b->uh.source =3D b->s_in6.sin6_port; > b->uh.dest =3D htons(dstport); > b->uh.len =3D b->ip6h.payload_len; > - > - b->ip6h.hop_limit =3D IPPROTO_UDP; > - b->ip6h.version =3D b->ip6h.nexthdr =3D b->uh.check =3D 0; > - b->uh.check =3D csum(&b->ip6h, ip_len, 0); > - b->ip6h.version =3D 6; > - b->ip6h.nexthdr =3D IPPROTO_UDP; > - b->ip6h.hop_limit =3D 255; > + b->uh.check =3D 0; > + b->uh.check =3D csum(&b->uh, payload_len, > + proto_ipv6_header_psum(payload_len, IPPROTO_UDP, > + src, dst)); > =20 > return tap_iov_len(c, &b->taph, ip_len); > } --=20 David Gibson | 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 --FTW1+uVO8CBVuS6k Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEO+dNsU4E3yXUXRK2zQJF27ox2GcFAmXlG04ACgkQzQJF27ox 2Gd4nQ/+PxWzejUUcAL2vsmzP5PK/roxRlYb5Z8u5HIUKCPy+Wv3KbQiZcjn6HvF 58dZ5+JKWw3nfxCeQmQDCtI4D+vnFrJ7VFaksxzj040JYaEYMmO3oqgAd+hQBwB5 /QMaJb7yZzGjxzUzqhbdIl7sLz5obYBjDZR+hPWa/e4Bi57JXa1oxaxeByPYbIVw BuFp3VTLYHdjnpTgFzVVTYUmMTdxqzlnSbbNTwyBAmwritb0LKR5h9ZbJmZYwh7N XghgKbieVK2emPTm5h1t9F6nxw6MYXE9ixl9/XHhNA18bwfVZubmiOBMSIyeutX9 4SX+59RM/PBTKWrlShKFI/gDGmRGpWTF1ZnU4nv82FL9r399F+E7a3N0zNzoGCmy pUr7qma9L0pPT9hO8lWbTOCMRwyxDau1KiResE1TdgLlUE+7kZnchyC6BD8OFe6W jZJ0GqQ5/WeEbpUGPwaV+159yK1dkF6uWBEimTAOKZ4qcnkyvMzlTRqY0UMItsU4 1nRcKZq33naxcCSvyAB7iJOCtWeZOTxcIOSaGQpimBityMYNojujjdKG/iLWSKnV S2fPKOTmDjj6SzPjRWJMqPvnjjdKfG0i7XKCvVwqTGaYnGPXA6/4d/vGx6uaN2UT rRgIK0WjOezaAMjHHsbR/Nf48Kcd8rUqDEi6Vj1Aet+Q2RM0Bjw= =rvTb -----END PGP SIGNATURE----- --FTW1+uVO8CBVuS6k--