From patchwork Tue Sep 12 13:44:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Patrick Rohr X-Patchwork-Id: 13381698 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB28FA952 for ; Tue, 12 Sep 2023 13:44:32 +0000 (UTC) Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BAC0510CE for ; Tue, 12 Sep 2023 06:44:31 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-59b52554914so50035187b3.0 for ; Tue, 12 Sep 2023 06:44:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1694526271; x=1695131071; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:from:subject:message-id :mime-version:date:from:to:cc:subject:date:message-id:reply-to; bh=rueJ3JxHkX3XXlIyOBcnanjjCPXo4cJgvmcjHONI/Yg=; b=Ka8c3Tcu09YWxVeKwgN4oBe1akHOMFS2M9NLQWjcB2YmfTdrcxlP6WJ0BR/Uf4kCKq woQbGOHnS30ykWycVuQR/5iEHFAwSVQw668RJcm05tJ3eTubqSRZapf6lWTjATcXYQEt tZG6GDnz5mksyq2N0QFPq1UL9ycgKgTOGT92D+rCmEnWUmFysb7Zh76xS/1stIvesgve 6SD30N8oBYnNk7DSOWuEN5/QOM6PWK4XrWTBf+MjPQvH1W32nvAsRquZHgRYBnkmyaxW F2IIaqgQPGQq7uLjinunkhLILRXd9FgoXpPD9+ZC53aPUuVJOTZLhwoIlrIko3XpZLHY cbuQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694526271; x=1695131071; h=content-transfer-encoding:cc:to:from:subject:message-id :mime-version:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=rueJ3JxHkX3XXlIyOBcnanjjCPXo4cJgvmcjHONI/Yg=; b=UW5948KmjuzKhjeepAk7ML6xd+jmf2zhcfym/9T7Angc9XVIzwC1AZzqOuy8q5Rjhn 5qhC2oaVLSvlgbqZG+xVf2UTfdbGlux40c46WiKoZaV3G4aRYSAqVXU48Ci3/0Y+ogWj j+9KQ3w9XgNYaJkMx9Bwe/DRSf/fNQpAz6dHF9dsXb11z65nQ47VOrqpVZAqFXeb2Gp9 tSx+lKGLXKTgc88d0XjqN03fLssChcYYEJeQ0+1HhY5Uc9HcMOsmtyQiLhRPCxNMO05D egMfMm8mnB1WkiSyQQYyoZ4Scykvy8FbFzuwQYgNmtdAYuxgs9d/Y4pa9TYxL6BUck0z IYBQ== X-Gm-Message-State: AOJu0YwgrqtwVkLjDZgu8HVdinCacuzqevK3nhZ9vsB5s5km61wufNRF f7WS3QPDoncMrFIEkiopt3yZgvjEAQ== X-Google-Smtp-Source: AGHT+IG5EKFnKPehZ1W1z5VMWPonhf+FfUC65fc1KkhCZbeJoMludCPnwy7sKW6W00637Pj8gOfqAg3evQ== X-Received: from prohr-desktop.mtv.corp.google.com ([2620:15c:211:200:4162:5280:8f7d:b119]) (user=prohr job=sendgmr) by 2002:a81:ae66:0:b0:58c:6ddd:d27c with SMTP id g38-20020a81ae66000000b0058c6dddd27cmr304743ywk.6.1694526270938; Tue, 12 Sep 2023 06:44:30 -0700 (PDT) Date: Tue, 12 Sep 2023 06:44:25 -0700 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.42.0.283.g2d96d420d3-goog Message-ID: <20230912134425.4083337-1-prohr@google.com> Subject: [PATCH net-next v2] net: add sysctl to disable rfc4862 5.5.3e lifetime handling From: Patrick Rohr To: "David S. Miller" Cc: Linux Network Development Mailing List , Patrick Rohr , " =?utf-8?q?Maciej_=C5=BBenczykowski?= " , Lorenzo Colitti , Jen Linkova X-Patchwork-Delegate: kuba@kernel.org This change adds a sysctl to opt-out of RFC4862 section 5.5.3e's valid lifetime derivation mechanism. RFC4862 section 5.5.3e prescribes that the valid lifetime in a Router Advertisement PIO shall be ignored if it less than 2 hours and to reset the lifetime of the corresponding address to 2 hours. An in-progress 6man draft (see draft-ietf-6man-slaac-renum-07 section 4.2) is currently looking to remove this mechanism. While this draft has not been moving particularly quickly for other reasons, there is widespread consensus on section 4.2 which updates RFC4862 section 5.5.3e. Cc: Maciej Żenczykowski Cc: Lorenzo Colitti Cc: Jen Linkova Signed-off-by: Patrick Rohr --- Documentation/networking/ip-sysctl.rst | 11 ++++++++ include/linux/ipv6.h | 1 + net/ipv6/addrconf.c | 38 +++++++++++++++++--------- 3 files changed, 37 insertions(+), 13 deletions(-) diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index a66054d0763a..7f21877e3f78 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -2304,6 +2304,17 @@ accept_ra_pinfo - BOOLEAN - enabled if accept_ra is enabled. - disabled if accept_ra is disabled. +ra_pinfo_rfc4862_5_5_3e - BOOLEAN + Use RFC4862 Section 5.5.3e to determine the valid lifetime of + an address matching a prefix sent in a Router Advertisement + Prefix Information Option. + + - If enabled, RFC4862 section 5.5.3e is used to determine + the valid lifetime of the address. + - If disabled, the PIO valid lifetime will always be honored. + + Default: 1 + accept_ra_rt_info_min_plen - INTEGER Minimum prefix length of Route Information in RA. diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 5883551b1ee8..f90cf8835ed4 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -35,6 +35,7 @@ struct ipv6_devconf { __s32 accept_ra_min_hop_limit; __s32 accept_ra_min_lft; __s32 accept_ra_pinfo; + __s32 ra_pinfo_rfc4862_5_5_3e; __s32 ignore_routes_with_linkdown; #ifdef CONFIG_IPV6_ROUTER_PREF __s32 accept_ra_rtr_pref; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 47d1dd8501b7..1ac23a37e8eb 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -204,6 +204,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .accept_ra_min_hop_limit= 1, .accept_ra_min_lft = 0, .accept_ra_pinfo = 1, + .ra_pinfo_rfc4862_5_5_3e = 1, #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1, .rtr_probe_interval = 60 * HZ, @@ -265,6 +266,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .accept_ra_min_hop_limit= 1, .accept_ra_min_lft = 0, .accept_ra_pinfo = 1, + .ra_pinfo_rfc4862_5_5_3e = 1, #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1, .rtr_probe_interval = 60 * HZ, @@ -2657,22 +2659,23 @@ int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev, stored_lft = ifp->valid_lft - (now - ifp->tstamp) / HZ; else stored_lft = 0; - if (!create && stored_lft) { + + /* RFC4862 Section 5.5.3e: + * "Note that the preferred lifetime of the + * corresponding address is always reset to + * the Preferred Lifetime in the received + * Prefix Information option, regardless of + * whether the valid lifetime is also reset or + * ignored." + * + * So we should always update prefered_lft here. + */ + update_lft = !create && stored_lft; + + if (update_lft && in6_dev->cnf.ra_pinfo_rfc4862_5_5_3e) { const u32 minimum_lft = min_t(u32, stored_lft, MIN_VALID_LIFETIME); valid_lft = max(valid_lft, minimum_lft); - - /* RFC4862 Section 5.5.3e: - * "Note that the preferred lifetime of the - * corresponding address is always reset to - * the Preferred Lifetime in the received - * Prefix Information option, regardless of - * whether the valid lifetime is also reset or - * ignored." - * - * So we should always update prefered_lft here. - */ - update_lft = 1; } if (update_lft) { @@ -6846,6 +6849,15 @@ static const struct ctl_table addrconf_sysctl[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "ra_pinfo_rfc4862_5_5_3e", + .data = &ipv6_devconf.ra_pinfo_rfc4862_5_5_3e, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, + }, #ifdef CONFIG_IPV6_ROUTER_PREF { .procname = "accept_ra_rtr_pref",