From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by passt.top (Postfix) with ESMTP id A63875A0082 for ; Thu, 17 Nov 2022 01:15:25 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668644124; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=z3vmb+7IgUVLgTXrAbMkgwx2FZUKcrxexUWeiFI3/ZI=; b=O1YV3I/9VMXkP7XITS2xMM+GUXpdPACdkejo4q2/opxrwuysNDvveDsWb9xQFAengM9Xqg N2piXASH78d9VZDjUwbFGpo6QqrZWd7K3B3r3fhxRfSocr55PYt4I8rENBhVzNUqX/xi50 /Nj8g6ClOd4ycI75FxMsyHt3FTE0c9I= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-15-_pAF66btN3a4S-TOZjXJeA-1; Wed, 16 Nov 2022 19:15:23 -0500 X-MC-Unique: _pAF66btN3a4S-TOZjXJeA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EFBD43C01DED; Thu, 17 Nov 2022 00:15:22 +0000 (UTC) Received: from maya.cloud.tilaa.com (ovpn-208-8.brq.redhat.com [10.40.208.8]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 943761121325; Thu, 17 Nov 2022 00:15:22 +0000 (UTC) Date: Thu, 17 Nov 2022 01:15:20 +0100 From: Stefano Brivio To: David Gibson Subject: Re: [PATCH 27/32] tcp: NAT IPv4-mapped IPv6 addresses like IPv4 addresses Message-ID: <20221117011520.4e42fe79@elisabeth> In-Reply-To: <20221116044212.3876516-28-david@gibson.dropbear.id.au> References: <20221116044212.3876516-1-david@gibson.dropbear.id.au> <20221116044212.3876516-28-david@gibson.dropbear.id.au> Organization: Red Hat MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-ID-Hash: SYKSSWSZPLKFJC6HLN4HHHW7DFIDEOJ3 X-Message-ID-Hash: SYKSSWSZPLKFJC6HLN4HHHW7DFIDEOJ3 X-MailFrom: sbrivio@redhat.com 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: On Wed, 16 Nov 2022 15:42:07 +1100 David Gibson wrote: > passt usually doesn't NAT, but it does do so for the remapping of the > gateway address to refer to the host. Currently we perform this NAT with > slightly different rules on both IPv4 addresses and IPv6 addresses, but not > on IPv4-mapped IPv6 addresses. This means we won't correctly handle the > case of an IPv4 connection over an IPv6 socket, which is possible on Linux > (and probably other platforms). By the way, I really think it's just Linux, I can't think of other examples. > Refactor tcp_conn_from_sock() to perform the NAT after converting either > address family into an inany_addr, so IPv4 and and IPv4-mapped addresses > have the same representation. > > With two new helpers this lets us remove the IPv4 and IPv6 specific paths > from tcp_conn_from_sock(). > > Signed-off-by: David Gibson > --- > inany.h | 30 ++++++++++++++++++++++++++-- > tcp.c | 62 ++++++++++++++++++++++++--------------------------------- > 2 files changed, 54 insertions(+), 38 deletions(-) > > diff --git a/inany.h b/inany.h > index 4e53da9..a677aa7 100644 > --- a/inany.h > +++ b/inany.h > @@ -30,11 +30,11 @@ union inany_addr { > * > * Return: IPv4 address if @addr is IPv4, NULL otherwise > */ > -static inline const struct in_addr *inany_v4(const union inany_addr *addr) > +static inline struct in_addr *inany_v4(const union inany_addr *addr) There must be a reason, but I can't understand why this change is needed here. > { > if (!IN6_IS_ADDR_V4MAPPED(&addr->a6)) > return NULL; > - return &addr->_v4mapped.a4; > + return (struct in_addr *)&addr->_v4mapped.a4; > } > > /** inany_equals - Compare two IPv[46] addresses > @@ -66,3 +66,29 @@ static inline void inany_from_af(union inany_addr *aa, int af, const void *addr) > assert(0); > } > } > + > +/** inany_from_sockaddr - Extract IPv[46] address and port number from sockaddr > + * @a: Pointer to store IPv[46] address This is aa below, I'm not sure why. > + * @port: Pointer to store port number, host order > + * @addr: struct sockaddr_in (IPv4) or struct sockaddr_in6 (IPv6) This became sa_ (needless to say, addr would make more sense). > + */ > +static inline void inany_from_sockaddr(union inany_addr *aa, in_port_t *port, > + const void *sa_) > +{ > + const struct sockaddr *sa = (const struct sockaddr *)sa_; > + > + if (sa->sa_family == AF_INET6) { > + struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)sa; > + > + inany_from_af(aa, AF_INET6, &sa6->sin6_addr); > + *port = ntohs(sa6->sin6_port); > + } else if (sa->sa_family == AF_INET) { > + struct sockaddr_in *sa4 = (struct sockaddr_in *)sa; > + > + inany_from_af(aa, AF_INET, &sa4->sin_addr); > + *port = ntohs(sa4->sin_port); > + } else { > + /* Not valid to call with other address families */ > + assert(0); > + } > +} > diff --git a/tcp.c b/tcp.c > index b05ed6c..fca5df4 100644 > --- a/tcp.c > +++ b/tcp.c > @@ -2724,6 +2724,29 @@ static void tcp_connect_finish(struct ctx *c, struct tcp_tap_conn *conn) > conn_flag(c, conn, ACK_FROM_TAP_DUE); > } > > +static void tcp_snat_inbound(const struct ctx *c, union inany_addr *addr) What this does is kind of obvious, still a comment would be nice. > +{ > + struct in_addr *addr4 = inany_v4(addr); > + > + if (addr4) { > + if (IN4_IS_ADDR_LOOPBACK(addr4) || > + IN4_IS_ADDR_UNSPECIFIED(addr4) || > + IN4_ARE_ADDR_EQUAL(addr4, &c->ip4.addr_seen)) > + *addr4 = c->ip4.gw; > + } else { > + struct in6_addr *addr6 = &addr->a6; > + > + if (IN6_IS_ADDR_LOOPBACK(addr6) || > + IN6_ARE_ADDR_EQUAL(addr6, &c->ip6.addr_seen) || > + IN6_ARE_ADDR_EQUAL(addr6, &c->ip6.addr)) { > + if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw)) > + *addr6 = c->ip6.gw; > + else > + *addr6 = c->ip6.addr_ll; > + } > + } > +} > + > /** > * tcp_tap_conn_from_sock() - Initialize state for non-spliced connection > * @c: Execution context > @@ -2744,43 +2767,10 @@ static void tcp_tap_conn_from_sock(struct ctx *c, union epoll_ref ref, > conn->ws_to_tap = conn->ws_from_tap = 0; > conn_event(c, conn, SOCK_ACCEPTED); > > - if (sa->sa_family == AF_INET6) { > - struct sockaddr_in6 sa6; > - > - memcpy(&sa6, sa, sizeof(sa6)); > - > - if (IN6_IS_ADDR_LOOPBACK(&sa6.sin6_addr) || > - IN6_ARE_ADDR_EQUAL(&sa6.sin6_addr, &c->ip6.addr_seen) || > - IN6_ARE_ADDR_EQUAL(&sa6.sin6_addr, &c->ip6.addr)) { > - struct in6_addr *src; > + inany_from_sockaddr(&conn->addr, &conn->sock_port, sa); > + conn->tap_port = ref.r.p.tcp.tcp.index; > > - if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw)) > - src = &c->ip6.gw; > - else > - src = &c->ip6.addr_ll; > - > - memcpy(&sa6.sin6_addr, src, sizeof(*src)); > - } > - > - inany_from_af(&conn->addr, AF_INET6, &sa6.sin6_addr); > - > - conn->sock_port = ntohs(sa6.sin6_port); > - conn->tap_port = ref.r.p.tcp.tcp.index; > - } else { > - struct sockaddr_in sa4; > - > - memcpy(&sa4, sa, sizeof(sa4)); > - > - if (IN4_IS_ADDR_LOOPBACK(&sa4.sin_addr) || > - IN4_IS_ADDR_UNSPECIFIED(&sa4.sin_addr) || > - IN4_ARE_ADDR_EQUAL(&sa4.sin_addr, &c->ip4.addr_seen)) > - sa4.sin_addr = c->ip4.gw; > - > - inany_from_af(&conn->addr, AF_INET, &sa4.sin_addr); > - > - conn->sock_port = ntohs(sa4.sin_port); > - conn->tap_port = ref.r.p.tcp.tcp.index; > - } > + tcp_snat_inbound(c, &conn->addr); > > tcp_seq_init(c, conn, now); > tcp_hash_insert(c, conn); -- Stefano