From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by passt.top (Postfix) with ESMTP id 3163D5A026D for ; Thu, 7 Sep 2023 03:01:53 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694048512; 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=r5t0798v2N3jWc7+6Bb0lQdtyW9bENX8nZiGmIpS/tY=; b=bxOhU9tdreFlepispaBFwldpORutxq6CMVy7CdK0S84SwQ4ZjZ5Mm8orlzQxtjSXb+kgd5 tjGDPT8nwhkuPY4p/84OfCzjk5H934QrnXgopO9ani3NCmi1Nr4nUxhBTefhU/9hbHGw0/ rvYrGByGs3VtWIVc9KyXb5HArjZKggg= Received: from mimecast-mx02.redhat.com (mx-ext.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-664-oiac_zj0NnyU7E69andRXw-1; Wed, 06 Sep 2023 21:01:49 -0400 X-MC-Unique: oiac_zj0NnyU7E69andRXw-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 D16CE3C0D873; Thu, 7 Sep 2023 01:01:48 +0000 (UTC) Received: from elisabeth (unknown [10.39.208.34]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3D1051121314; Thu, 7 Sep 2023 01:01:48 +0000 (UTC) Date: Thu, 7 Sep 2023 03:01:40 +0200 From: Stefano Brivio To: David Gibson Subject: Re: [PATCH v2 05/10] flow: Introduce struct flowside, space for uniform tracking of addresses Message-ID: <20230907030140.5dd18377@elisabeth> In-Reply-To: <20230828054146.48673-6-david@gibson.dropbear.id.au> References: <20230828054146.48673-1-david@gibson.dropbear.id.au> <20230828054146.48673-6-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: E6GJETIIIWWCGFWABAHAVTW5W7KCM6XI X-Message-ID-Hash: E6GJETIIIWWCGFWABAHAVTW5W7KCM6XI 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: 3.3.8 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: On Mon, 28 Aug 2023 15:41:41 +1000 David Gibson wrote: > Handling of each protocol needs some degree of tracking of the addresses > and ports at the end of each connection or flow. Sometimes that's explicit > (as in the guest visible addresses for TCP connections), sometimes implicit > (the bound and connected addresses of sockets). > > To allow more general abd robust handling, and more consistency across > protocols we want to uniformly track the address and port at each end of > the connection. Furthermore, because we allow port remapping, and we > sometimes need to apply NAT, the addresses and ports can be different as > seen by the guest/namespace and as by the host. > > Introduce 'struct flowside' to keep track of the address and ports of a > flow from a single "side" (guest or host). Store two of these in the > common fields of a flow to track that information for both sides. > > For now we just introduce the structure and fields themselves, along with > some simple helpers. Later patches will actually use these to store useful > information. > > Signed-off-by: David Gibson > --- > flow.c | 22 ++++++++++++++++++++++ > flow.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 70 insertions(+) > > diff --git a/flow.c b/flow.c > index 12ca8db..a93cf8c 100644 > --- a/flow.c > +++ b/flow.c > @@ -7,6 +7,7 @@ > > #include > #include > +#include > > #include "util.h" > #include "passt.h" > @@ -24,6 +25,27 @@ const char *flow_type_str[] = { > /* Global Flow Table */ > union flow flowtab[FLOW_MAX]; > > +/** flowside_fmt - Format a flowside as a string > + * @fs: flowside to format > + * @buf: Buffer into which to store the formatted version > + * @size: Size of @buf > + * > + * Return: pointer to formatted string describing @fs, or NULL on error > + */ > +/* cppcheck-suppress unusedFunction */ > +const char *flowside_fmt(const struct flowside *fs, char *buf, size_t size) > +{ > + char ebuf[INET6_ADDRSTRLEN], fbuf[INET6_ADDRSTRLEN]; > + > + if (!inet_ntop(AF_INET6, &fs->eaddr, ebuf, sizeof(ebuf)) > + || !inet_ntop(AF_INET6, &fs->faddr, fbuf, sizeof(fbuf))) For consistency (also with flowside_complete() below): if (!inet_ntop(AF_INET6, &fs->eaddr, ebuf, sizeof(ebuf)) || !inet_ntop(AF_INET6, &fs->faddr, fbuf, sizeof(fbuf))) > + return NULL; > + > + snprintf(buf, size, "[%s]:%hu <-> [%s]:%hu", fbuf, fs->fport, > + ebuf, fs->eport); > + return (const char *)buf; > +} > + > /** > * flow_table_compact() - Perform compaction on flow table > * @c: Execution context > diff --git a/flow.h b/flow.h > index e212796..9891fcb 100644 > --- a/flow.h > +++ b/flow.h > @@ -18,11 +18,59 @@ extern const char *flow_type_str[]; > #define FLOW_TYPE(f) \ > ((f)->type <= FLOW_MAX ? flow_type_str[(f)->type] : "?") > > +/** > + * struct flowside - Describes a logical packet flow as seen from one "side" > + * @eaddr: Endpoint address (remote address from passt's PoV) > + * @faddr: Forwarding address (local address from passt's PoV) > + * @eport: Endpoint port > + * @fport: Forwarding port > + */ > +struct flowside { > + union inany_addr faddr; > + union inany_addr eaddr; > + in_port_t fport, eport; I guess always valid, but uncommon (compared to in_port_t x; in_port_t y;)? > +}; > + > +/** flowside_from_af - Initialize a flowside from addresses > + * @fs: flowside to initialize > + * @af: Address family (AF_INET or AF_INET6) > + * @faddr: Forwarding address (pointer to in_addr or in6_addr) > + * @fport: Forwarding port > + * @eaddr: Endpoint address (pointer to in_addr or in6_addr) > + * @eport: Endpoint port > + */ > +static inline void flowside_from_af(struct flowside *fs, int af, > + const void *faddr, in_port_t fport, > + const void *eaddr, in_port_t eport) > +{ > + inany_from_af(&fs->faddr, af, faddr); > + inany_from_af(&fs->eaddr, af, eaddr); > + fs->fport = fport; > + fs->eport = eport; > +} > + > +/** flowside_complete - Check if flowside is fully initialized > + * @fs: flowside to check > + */ > +static inline bool flowside_complete(const struct flowside *fs) > +{ > + return !IN6_IS_ADDR_UNSPECIFIED(&fs->faddr) && > + !IN6_IS_ADDR_UNSPECIFIED(&fs->eaddr) && > + fs->fport != 0 && fs->eport != 0; Zero is reserved for TCP (which could be problematic anyway if we try to match things), but for UDP a "zero" port can actually be used (in the probably desuete sense of "no port"). Maybe we should use -1 instead? > +} > + > +#define FLOWSIDE_STRLEN (2*(INET6_ADDRSTRLEN+8) + 6) For consistency: "(2 * INET6_ADDRSTRLEN + 8) + 6)". Limited to the usage I've seen in 6/10 (maybe I'm ignoring something): is it worth it to have flowside_fmt() as a function forming a string, rather than something calling debug() with what we want...? At the moment we have tap_packet_debug(), admittedly not very elegant but perhaps more terse than this. -- Stefano