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 E25345A026A for ; Tue, 18 Oct 2022 14:08:13 +0200 (CEST) Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4MsCLH3zbVz4xG9; Tue, 18 Oct 2022 23:08:07 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=201602; t=1666094887; bh=tIpv6b8On5UmBQyi2bU46RsrYusP1po1yRiAFGGPwiQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MnC5ASVggZN8U7Sevwdn/Kc4XkjpHpWqnXKLQRYe/p4RCMeBU9HCfyWixhQHmRS8e 4fVbA/+LuV25HzJNcT5+C5Y9ht2+zjG8QPUhIWNWQtLOtfIGKStye5DGNzrNJDdmHG OrFlH/At+8BGoqgx8SUNvbtLb7lPpSRXs/wxREq4= Date: Tue, 18 Oct 2022 23:05:51 +1100 From: David Gibson To: Stefano Brivio Subject: Re: [PATCH 01/14] Add csum_icmp6() helper for calculating ICMPv6 checksums Message-ID: References: <20221017085807.473470-1-david@gibson.dropbear.id.au> <20221017085807.473470-2-david@gibson.dropbear.id.au> <20221018050101.2b437d40@elisabeth> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="sjypo/Tipodmaw0K" Content-Disposition: inline In-Reply-To: <20221018050101.2b437d40@elisabeth> Message-ID-Hash: SKQNFUP24Y3C5OPFIW7RG7HYHHGK3DA6 X-Message-ID-Hash: SKQNFUP24Y3C5OPFIW7RG7HYHHGK3DA6 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: 3.3.3 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: --sjypo/Tipodmaw0K Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Oct 18, 2022 at 05:01:01AM +0200, Stefano Brivio wrote: > On Mon, 17 Oct 2022 19:57:54 +1100 > David Gibson wrote: >=20 > > At least two places in passt calculate ICMPv6 checksums, ndp() and > > tap_ip_send(). Add a helper to handle this calculation in both places. > > For future flexibility, the new helper takes parameters for the fields = in > > the IPv6 pseudo-header, so an IPv6 header or pseudo-header doesn't need= to > > be explicitly constructed. It also allows the ICMPv6 header and payloa= d to > > be in separate buffers, although we don't use this yet. > >=20 > > Signed-off-by: David Gibson > > --- > > checksum.c | 27 +++++++++++++++++++++++++++ > > checksum.h | 7 +++++++ > > ndp.c | 5 +---- > > tap.c | 6 ++---- > > 4 files changed, 37 insertions(+), 8 deletions(-) > >=20 > > diff --git a/checksum.c b/checksum.c > > index 56ad01e..0e207c8 100644 > > --- a/checksum.c > > +++ b/checksum.c > > @@ -52,6 +52,8 @@ > > #include > > #include > > =20 > > +#include > > + > > /** > > * sum_16b() - Calculate sum of 16-bit words > > * @buf: Input buffer > > @@ -105,6 +107,31 @@ uint16_t csum_unaligned(const void *buf, size_t le= n, uint32_t init) > > return (uint16_t)~csum_fold(sum_16b(buf, len) + init); > > } > > =20 > > +/** > > + * csum_icmp6() - Calculate checksum for an ICMPv6 packet >=20 > "Calculate and set" ...? Done. > > + * @icmp6hr: ICMPv6 header, initialized apart from checksum > > + * @saddr: IPv6 source address > > + * @daddr: IPv6 destination address > > + * @payload: ICMP packet payload > > + * @len: Length of @payload (not including ICMPv6 header) > > + */ > > +void csum_icmp6(struct icmp6hdr *icmp6hr, > > + const struct in6_addr *saddr, > > + const struct in6_addr *daddr, >=20 > I think: > const struct in6_addr *saddr, const struct in6_addr *daddr, >=20 > would be easier on eyes. Done. Not sure why I did it that way in the first place. > > + 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(*icmp6hr)) + htons(IPPROTO_ICMPV6); >=20 > Maybe: >=20 > uint32_t psum =3D sum_16b(saddr, sizeof(*saddr)) + > sum_16b(daddr, sizeof(*daddr)) + > htons(len + sizeof(*icmp6hr)) + htons(IPPROTO_ICMPV6); >=20 > for me, it turns things from "sum a bunch of things" to "addresses and > something else". Fair enough, done. > > + > > + icmp6hr->icmp6_cksum =3D 0; > > + /* Add in partial checksum for the ICMPv6 header alone */ > > + psum +=3D sum_16b(icmp6hr, sizeof(*icmp6hr)); > > + icmp6hr->icmp6_cksum =3D csum_unaligned(payload, len, psum); > > +} > > + > > /** > > * csum_tcp4() - Calculate TCP checksum for IPv4 and set in place > > * @iph: Packet buffer, IP header > > diff --git a/checksum.h b/checksum.h > > index 5418406..2c72200 100644 > > --- a/checksum.h > > +++ b/checksum.h > > @@ -6,9 +6,16 @@ > > #ifndef CHECKSUM_H > > #define CHECKSUM_H > > =20 > > +struct icmp6hdr; > > + > > uint32_t sum_16b(const void *buf, size_t len); > > uint16_t csum_fold(uint32_t sum); > > uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init); > > +void csum_icmp6(struct icmp6hdr *ih, > > + const struct in6_addr *saddr, > > + const struct in6_addr *daddr, > > + const void *payload, > > + size_t len); >=20 > It looks a bit like Haskell. ;) I would really use the horizontal space > we have. >=20 > > void csum_tcp4(struct iphdr *iph); > > uint16_t csum(const void *buf, size_t len, uint32_t init); > > =20 > > diff --git a/ndp.c b/ndp.c > > index dec36a9..03f1d06 100644 > > --- a/ndp.c > > +++ b/ndp.c > > @@ -189,10 +189,7 @@ dns_done: > > ip6hr->saddr =3D c->ip6.addr_ll; > > =20 > > ip6hr->payload_len =3D htons(sizeof(*ihr) + len); > > - ip6hr->hop_limit =3D IPPROTO_ICMPV6; > > - ihr->icmp6_cksum =3D 0; > > - ihr->icmp6_cksum =3D csum_unaligned(ip6hr, sizeof(*ip6hr) + > > - sizeof(*ihr) + len, 0); > > + csum_icmp6(ihr, &ip6hr->saddr, &ip6hr->daddr, ihr + 1, len); >=20 > Nice to see this all going away! >=20 > > ip6hr->version =3D 6; > > ip6hr->nexthdr =3D IPPROTO_ICMPV6; > > diff --git a/tap.c b/tap.c > > index 8b6d9bc..aafc92b 100644 > > --- a/tap.c > > +++ b/tap.c > > @@ -191,10 +191,8 @@ void tap_ip_send(const struct ctx *c, const struct= in6_addr *src, uint8_t proto, > > } else if (proto =3D=3D IPPROTO_ICMPV6) { > > struct icmp6hdr *ih =3D (struct icmp6hdr *)(ip6h + 1); > > =20 > > - ih->icmp6_cksum =3D 0; > > - ih->icmp6_cksum =3D csum_unaligned(ip6h, > > - len + sizeof(*ip6h), > > - 0); > > + csum_icmp6(ih, &ip6h->saddr, &ip6h->daddr, > > + ih + 1, len - sizeof(*ih)); > > } > > ip6h->version =3D 6; > > ip6h->nexthdr =3D proto; >=20 --=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 --sjypo/Tipodmaw0K Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEoULxWu4/Ws0dB+XtgypY4gEwYSIFAmNOlpUACgkQgypY4gEw YSK5Dg/9FfTa9v1U9xsOm+c0Db8uOo1gzNIqXzjaPKXlFDb7Jqwu6WIVWO/bndHz CWQBS7XZdn2kxr1ETg7Afe/6WwUCHJ9Y5RrrhtobmePEcjfQ/kTeN1YIUNVGlhCw Zl5uHJv7P9MOUum179mQDIN83bOkbI7SXYppe0Q4XR1K8t06DTInC8itizFlujij hypWPLBj/6xoQKdXPVhAcKAUJRcxke5U/QCyXfly2S0oDLCbULkgFYuFN1ri3txR ukgM/ZTrqutqnkuEvd+AFtbdOs18n78RwB2pIK3Mi0OvrFK6qtJnT5oxUf4IaG2I 3DbhNmg2ctelw6ZsUINV0hP3sZRm20OkAgRqmA+EZI94+KK/pAUpRS/cQKteiufn IqKgtfxioBHY+v8KUDJrx3LbTYo0hgxzqwk16Qle+yRXAYB0X8LRs4ysxxbcIKKE XVnGp4zjWLJ50Q52BWzDegeT0BxlxyNekxb1ZKFCtDpd3Ce9cnkIgXLRgm0GrtnL 7PKN0/jXb9K2fKBcQpskm7RydImbtS/WWqI6FQlSjh1O/fEelWbckWy9p6umaERk MoLJlk5cmKqAod354zx3U5ojLB5U7CPgcbOtvUNQINGpyapLucK/S9ilIcQLrOgv RpbOOwllO6cnTBSDWzyLS5DRKSL+D78ZHp3xjJ6oirVW111LOIU= =Jr4o -----END PGP SIGNATURE----- --sjypo/Tipodmaw0K--