From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f48.google.com (mail-pj1-f48.google.com [209.85.216.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5B10A299A81 for ; Mon, 30 Mar 2026 19:16:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.48 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774898196; cv=none; b=eLTCHsEuzDcM7eSfchZKUx9GqZmizU7KtTztglq5p0pC9L5bDl68JfQkKNS4Bg1gNP9GTrlUacNa9+FBdNCBwuULVm8m7taTwNhSvllSwmtaLnquuhKsBeK/0NmMxSMBC0RMLDMIprH8ZYvEwBb+Frk/efS3cyQ5J+ei0q8+dlE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774898196; c=relaxed/simple; bh=WW0vISqU8GwrmrIC4NHoR+TFPQ7BlX0/FvDVbKYURp4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KpDURiZl9fj22ikTyh3ECsHKqHmlsUI18aBrBBPkkc8Jtt1J8rjK1OXdOF1vDMdP0P6TPbtStYEgqaxdrLW2g9aaHjDTvwJUTyEmhmqNL+tVFDKGqmQuToe8ubu0lINS9IBrBbmc6ITCIGhNu8u8INs4rAjJhrG44j0ljrgw3do= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=KH8Kt3K7; arc=none smtp.client-ip=209.85.216.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KH8Kt3K7" Received: by mail-pj1-f48.google.com with SMTP id 98e67ed59e1d1-35d8e548a05so2929446a91.1 for ; Mon, 30 Mar 2026 12:16:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1774898195; x=1775502995; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=O2s2FZ+Hg0ngcpnnbi9FLabs6QrxAbJsZ+G4M5k6jv8=; b=KH8Kt3K77F2LlBQS+iFCqXR5z4CHC6rmBPlVOV5mEczvUjlP4UmBv2a7PuSoaYGPwS TJpzbbHv/nSti8yo2uXQsT4hWbCIskio+BqNm0N0trigE1GPLkxfFKAmAK1xJzpnE3is FacWmsKC8nFodfYaNsulNWj6w3eoWyLqGHinY4cZicRbuOItV/1fweUNfxIT3TsfGvAJ MNv9qHW7Jc77fjUOTCD8lhsfIMwF6MgCrNaPOnxIx3zS28NeEdDyhh9cU7qhiwk05ngO qk3W2Gjlxy+vlMqIFZMZdNFPfWklXrX+7dAdO+9Y07JgKvXbDFcbKJEUQ2Nh+03zshiE CyNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774898195; x=1775502995; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=O2s2FZ+Hg0ngcpnnbi9FLabs6QrxAbJsZ+G4M5k6jv8=; b=onMYpyc5JUUHmaLwdgq7WQKaloPfWeX71cdBgZ435ngvjwdWZ8DtBHnJ3u+c4eQ7N3 vlJw3DOIGcDDNPepjhD+YQlH7sKZRlnTzVNCpPU6x1QMHMgOwVmF4xrZRoLMXc8dDFhL Gw80jagxk7kZzZ8ZrJ7hXgRScsf76NV6XqtOvMUwEBKCzPThxSpd/8ct0fjqqZUW/+jE UIU8ovIZcS1OXnMfY6xlyrqI/1j/qfO61hy58yzEltnDNd6RLruK/1Xtxhu6h5xLzGzf 3uwxrhEJSO1hZSxDJ+BkYRWjBbuN45G2Z8duFfTN1k0JdMxv5GduVWV7uB5nXZpvp5qh anvw== X-Forwarded-Encrypted: i=1; AJvYcCXmsmM6+6JOGQZFz84Dzb/6qmIR+UhUzABGdcO23cqJY8/fX6l8fP0NmQ9EMXb5DPZrJuMhpmU=@lists.linux.dev X-Gm-Message-State: AOJu0Yxr7Mnc3Oejm5rbEaLJDxZztliIS6e+KwRS5x8X7M07ssSrKPp3 16kNmwzyWPZ1v8L1gbnqNmFT6oZKAcXpngIg3GC8B4oArQcDilRmqV1L X-Gm-Gg: ATEYQzy+pEJyUSu47vbVWMF9DD/y4nNVlAv9Q1eBeo0G/aFveHr8v9RWw4oJy61pwaI OlCQekSWyqtN8hFYnuICoTQ9/mbwVI80dG55rV7TyeAmWm0rkzzXbywF9rKI/ouEgIeLqCsLflz uKPt2SgoDRpeCtoWmTYaFVMyMnXvCUDXbAi4Bnj19h0zWWSx6DJGIUYsWuiaxBOUM4wZEcGbTXo JFkUv+vZVuGzj3JGbjBXMCem/dhK8iJ24j2F+kePSs+/6sMShUOVIrgLbJle7waXhRY1UXpiqQN FAUhuvgMpaldme6BBlIlmSU8mWe9Unds7E5TjNWFOqsYrRXXRtEs8emlRr8srq5yo/qAxBTxZHN flEzkFEcc7bzlkVKxvkYFBuUB98b0r4DEbactTKay9sqbcBH2EjankKCtqZqy67afPqb8yY9Acx htOBlIhTJpk2fg4yGLmQM6eZcc8fp00utpLj34j3NX X-Received: by 2002:a17:90b:3c8b:b0:35b:a1b6:5bf5 with SMTP id 98e67ed59e1d1-35c30146fe2mr12855192a91.31.1774898194656; Mon, 30 Mar 2026 12:16:34 -0700 (PDT) Received: from DESKTOP-82PPU4A.localdomain ([202.8.116.192]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-35d950d9b12sm9627178a91.17.2026.03.30.12.16.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Mar 2026 12:16:34 -0700 (PDT) From: Ujjal Roy To: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Nikolay Aleksandrov , Ido Schimmel , David Ahern , Shuah Khan , Andy Roulin , Yong Wang , Petr Machata Cc: Ujjal Roy , bridge@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH net-next v2 1/5] ipv4: igmp: get rid of IGMPV3_{QQIC,MRC} and simplify calculation Date: Mon, 30 Mar 2026 19:16:07 +0000 Message-ID: <20260330191611.16929-2-royujjal@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260330191611.16929-1-royujjal@gmail.com> References: <20260330191611.16929-1-royujjal@gmail.com> Precedence: bulk X-Mailing-List: bridge@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Get rid of the IGMPV3_MRC macro and use the igmpv3_mrt() API to calculate the Max Resp Time from the Maximum Response Code. Similarly, for IGMPV3_QQIC, use the igmpv3_qqi() API to calculate the Querier's Query Interval from the QQIC field. Signed-off-by: Ujjal Roy --- include/linux/igmp.h | 78 +++++++++++++++++++++++++++++++++++---- net/bridge/br_multicast.c | 2 +- net/ipv4/igmp.c | 6 +-- 3 files changed, 74 insertions(+), 12 deletions(-) diff --git a/include/linux/igmp.h b/include/linux/igmp.h index 073b30a9b850..3c12c0a63492 100644 --- a/include/linux/igmp.h +++ b/include/linux/igmp.h @@ -92,15 +92,77 @@ struct ip_mc_list { struct rcu_head rcu; }; +/* RFC3376, relevant sections: + * - 4.1.1. Maximum Response Code + * - 4.1.7. QQIC (Querier's Query Interval Code) + * + * If Max Resp Code >= 128, Max Resp Code represents a floating-point + * value as follows: + * If QQIC >= 128, QQIC represents a floating-point value as follows: + * + * 0 1 2 3 4 5 6 7 + * +-+-+-+-+-+-+-+-+ + * |1| exp | mant | + * +-+-+-+-+-+-+-+-+ + */ +#define IGMPV3_FP_EXP(value) (((value) >> 4) & 0x07) +#define IGMPV3_FP_MAN(value) ((value) & 0x0f) + +/* IGMPV3 floating-point exponential field threshold */ +#define IGMPV3_EXP_MIN_THRESHOLD 128 + /* V3 exponential field decoding */ -#define IGMPV3_MASK(value, nb) ((nb)>=32 ? (value) : ((1<<(nb))-1) & (value)) -#define IGMPV3_EXP(thresh, nbmant, nbexp, value) \ - ((value) < (thresh) ? (value) : \ - ((IGMPV3_MASK(value, nbmant) | (1<<(nbmant))) << \ - (IGMPV3_MASK((value) >> (nbmant), nbexp) + (nbexp)))) - -#define IGMPV3_QQIC(value) IGMPV3_EXP(0x80, 4, 3, value) -#define IGMPV3_MRC(value) IGMPV3_EXP(0x80, 4, 3, value) + +/* + * IGMPv3 QQI/MRT 8-bit exponential field decode. + * + * RFC3376, 4.1.1 & 4.1.7. defines the decoding formula: + * 0 1 2 3 4 5 6 7 + * +-+-+-+-+-+-+-+-+ + * |1| exp | mant | + * +-+-+-+-+-+-+-+-+ + * Max Resp Time = (mant | 0x10) << (exp + 3) + * QQI = (mant | 0x10) << (exp + 3) + */ +static inline unsigned long igmpv3_exp_field_decode(const u8 code) +{ + /* RFC3376, relevant sections: + * - 4.1.1. Maximum Response Code + * - 4.1.7. QQIC (Querier's Query Interval Code) + */ + if (code < IGMPV3_EXP_MIN_THRESHOLD) { + return (unsigned long)code; + } else { + unsigned long mc_man, mc_exp; + + mc_exp = IGMPV3_FP_EXP(code); + mc_man = IGMPV3_FP_MAN(code); + + return ((mc_man | 0x10) << (mc_exp + 3)); + } +} + +/* Calculate Max Resp Time from Maximum Response Code */ +static inline unsigned long igmpv3_mrt(const struct igmpv3_query *ih3) +{ + /* RFC3376, relevant sections: + * - 4.1.1. Maximum Response Code + * - 8.3. Query Response Interval + */ + return igmpv3_exp_field_decode(ih3->code); +} + +/* Calculate Querier's Query Interval from Querier's Query Interval Code */ +static inline unsigned long igmpv3_qqi(const struct igmpv3_query *ih3) +{ + /* RFC3376, relevant sections: + * - 4.1.7. QQIC (Querier's Query Interval Code) + * - 8.2. Query Interval + * - 8.12. Older Version Querier Present Timeout + * (the [Query Interval] in the last Query received) + */ + return igmpv3_exp_field_decode(ih3->qqic); +} static inline int ip_mc_may_pull(struct sk_buff *skb, unsigned int len) { diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 881d866d687a..9fec76e887bc 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -3518,7 +3518,7 @@ static void br_ip4_multicast_query(struct net_bridge_mcast *brmctx, goto out; max_delay = ih3->code ? - IGMPV3_MRC(ih3->code) * (HZ / IGMP_TIMER_SCALE) : 1; + igmpv3_mrt(ih3) * (HZ / IGMP_TIMER_SCALE) : 1; } else { goto out; } diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index a674fb44ec25..8c6102737096 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -991,7 +991,7 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb, * different encoding. We use the v3 encoding as more likely * to be intended in a v3 query. */ - max_delay = IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE); + max_delay = igmpv3_mrt(ih3)*(HZ/IGMP_TIMER_SCALE); if (!max_delay) max_delay = 1; /* can't mod w/ 0 */ } else { /* v3 */ @@ -1006,7 +1006,7 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb, ih3 = igmpv3_query_hdr(skb); } - max_delay = IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE); + max_delay = igmpv3_mrt(ih3)*(HZ/IGMP_TIMER_SCALE); if (!max_delay) max_delay = 1; /* can't mod w/ 0 */ WRITE_ONCE(in_dev->mr_maxdelay, max_delay); @@ -1016,7 +1016,7 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb, * configured value. */ in_dev->mr_qrv = ih3->qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv); - in_dev->mr_qi = IGMPV3_QQIC(ih3->qqic)*HZ ?: IGMP_QUERY_INTERVAL; + in_dev->mr_qi = igmpv3_qqi(ih3)*HZ ?: IGMP_QUERY_INTERVAL; /* RFC3376, 8.3. Query Response Interval: * The number of seconds represented by the [Query Response -- 2.43.0