From nobody Tue Apr 7 13:45:50 2026 Received: from mail-pf1-f178.google.com (mail-pf1-f178.google.com [209.85.210.178]) (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 D4F433C3C1B for ; Fri, 3 Apr 2026 15:01:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.178 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775228470; cv=none; b=u70MorczyozvMXSxhUvurmPviuA48Ez7eWS8bqJwWhJQbX8QtKAEcFEjJBADXjhC0/5XjSUNeHhycOAWveMC7X+v1BHYA33AhlX0kTmZwmf8Aazzt/AeoZPaGjJj6TUa9Xck/9V1gsz941UcbG1WZbcYzMKPWu3IMEVz0RdH1wA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775228470; c=relaxed/simple; bh=J0qBZOFYr25CwqolwkVoKoYOv65Rm2yGyYDO9qaRe6M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TyhVBeH0YKU9iqF39JsNWdt2n2SV5PHoCuPJi+b7Kt9paCyXlM9aoh+U/Meml9K8a8voPOhw/aBOOpdSumDEyZLMYmF/7z+0o3w1LfuaLchcm7MEFJHKMPCoM/JDN/rao487qwPpmPlQN1AAUwVQEopYf4hb/kaVVDwRYbOdT7I= 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=rtPcVAQw; arc=none smtp.client-ip=209.85.210.178 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="rtPcVAQw" Received: by mail-pf1-f178.google.com with SMTP id d2e1a72fcca58-82c70e4654eso921324b3a.2 for ; Fri, 03 Apr 2026 08:01:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1775228467; x=1775833267; darn=vger.kernel.org; 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=Cej7nCKLEwnUD6W7mDHvwY/cOSNtwOIhgAuZzAFc2ac=; b=rtPcVAQwC/sZRlIb3dEPBgx5/WeETNEZqotbWkfNVJQJlWr2gb+683OTMtohMlxkiv oncaa/34HknqphnVY6jfAC8LSZUTp9fvZEj44duUAErBi/lvQEC5mSTzaWwAiDS67XF3 BZQkdX2gG22Xu0T/gQOcyZSWCmHzJCOPyVC+3ZNNdJNo9TQj/u6OkvTgHw1Owbnno9ME dLY5In3cwslpwb7DC/yysUeaqD7K6hQ1VvqHNfhEOJg0c7IsLqNNT0EPxmiUuhcqrFua th7+rgNOcJ/dGx7hBSzYGbsZvUdJjRdoNQeR9HcrJAqxtqzPlVCDle5LVxW4h2Md56FE HDGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775228467; x=1775833267; 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=Cej7nCKLEwnUD6W7mDHvwY/cOSNtwOIhgAuZzAFc2ac=; b=QH+1Gep8oqnR3wEGOflT3RfPtte1pvN1Ej2PmE+ALZBpx3NcRvMgqNWwqAICyLbc+p OyGTWHa9QI2axxXbRRalAaDNwFMh2IR1UlO41DmOEvsi4xjKE6IMi6sSGWE89EVYs5/c JQPMn6VHO1hzmk8JNlcP1SmNu+N8DXEV701dMmHO7gE4A35AUZwdOXCGI6CVWEc5jK2C SAgXp+QzO0FEPnZ0tFETYZq3j/FFpgDJKQj0P4UegW5xXdn4PWCxDCiWkYfvIeRhE6sS 9ahvout5sf47xck4sdx9ffSDKPou6QNCrkwoNng9cmxHHTw/wLbdATnTO2O/7wv/9RCc sQlg== X-Forwarded-Encrypted: i=1; AJvYcCUun4Udgicpi1SKBaRrZu+CT0fdXb5igcuDq2rqEZGKWo328aAR4SwwOzJJh1Inq3weTPXnq1lG8eoYboQ=@vger.kernel.org X-Gm-Message-State: AOJu0YySZNa5icTDLCPkGvYKEJ3nHwcB6O3xfb+r28Mom+A7/qC7H3jG 7uZC9XeglMqQQBIP/UhjNipx6Kezi0H5qZTp2BylSJlsGQj658T/cnYtD41rxNgPIXI= X-Gm-Gg: ATEYQzwUmyPPHIkhebn4noWXnO5OSvxPWm57We35VHLvHqRiU5jxaGX6hk8Gmr0851h WJMSN0ahhLi8jF+xW7GIqeYHBu4UrWcD9V9h1aD9bKWw1wJ/9zPkhFQAPpLmTycLohj2YUoA8gu 3T9guBRPPzFtySlWtURQJsPaqBkJLGwM18+cdaSbBYBwU+mdLuq7sdh204yeMuQY1L39wyvH+Lv Mv0gflMpWU7XQPeEPASUgHPRVUP92x9ysx+wuoFd91csagILU4kvdRJE5RH5DJJ3UimHBBTFpCQ qID7jfnYu5vQqmfEeO0D/MNKSy78kmYmF62fOrrqnt1t/ArR+Yv7XzB8WTaMOamfDmFLwB20fhv C7CW2SGKO4Ks6CBrr/XArNnctTB8gYGt2x2C83XeGfjSdeB6Zh8LG12o+ON+paR3ppQXad9LzNF GdOlhKHAIr3QStzg/J5z6es7wtEAthg97NvISemUQ0 X-Received: by 2002:a05:6a00:8018:b0:82c:215d:5e9d with SMTP id d2e1a72fcca58-82d0db6bfc5mr3316415b3a.32.1775228467048; Fri, 03 Apr 2026 08:01:07 -0700 (PDT) Received: from DESKTOP-82PPU4A.localdomain ([202.8.116.192]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-82cf9ca79basm7789483b3a.58.2026.04.03.08.01.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Apr 2026 08:01:05 -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 v3 1/5] ipv4: igmp: get rid of IGMPV3_{QQIC,MRC} and simplify calculation Date: Fri, 3 Apr 2026 15:00:46 +0000 Message-ID: <20260403150050.1235-2-royujjal@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260403150050.1235-1-royujjal@gmail.com> References: <20260403150050.1235-1-royujjal@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 | 84 +++++++++++++++++++++++++++++++++++---- net/bridge/br_multicast.c | 2 +- net/ipv4/igmp.c | 6 +-- 3 files changed, 80 insertions(+), 12 deletions(-) diff --git a/include/linux/igmp.h b/include/linux/igmp.h index 073b30a9b850..0624410e75c6 100644 --- a/include/linux/igmp.h +++ b/include/linux/igmp.h @@ -92,15 +92,83 @@ struct ip_mc_list { struct rcu_head rcu; }; =20 +/* RFC3376, relevant sections: + * - 4.1.1. Maximum Response Code + * - 4.1.7. QQIC (Querier's Query Interval Code) + * + * For both MRC and QQIC, values >=3D 128 use the same floating-point + * encoding 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)>=3D32 ? (value) : ((1<<(nb))-1) & (va= lue)) -#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 QQIC/MRC 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 =3D (mant | 0x10) << (exp + 3) + * QQI =3D (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 code; + } else { + unsigned long mc_man, mc_exp; + + mc_exp =3D IGMPV3_FP_EXP(code); + mc_man =3D IGMPV3_FP_MAN(code); + + return (mc_man | 0x10) << (mc_exp + 3); + } +} + +/* Calculate Max Resp Time from Maximum Response Code + * + * After decode, MRC represents the Maximum Response Time (MRT) in units + * of 0.1 seconds (100 ms). + */ +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 + * + * After decode, QQIC represents the Querier's Query Interval in units + * of seconds. + */ +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); +} =20 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; =20 max_delay =3D 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..d7eff36d98c3 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 =3D IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE); + max_delay =3D igmpv3_mrt(ih3) * (HZ / IGMP_TIMER_SCALE); if (!max_delay) max_delay =3D 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 =3D igmpv3_query_hdr(skb); } =20 - max_delay =3D IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE); + max_delay =3D igmpv3_mrt(ih3) * (HZ / IGMP_TIMER_SCALE); if (!max_delay) max_delay =3D 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 =3D ih3->qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv); - in_dev->mr_qi =3D IGMPV3_QQIC(ih3->qqic)*HZ ?: IGMP_QUERY_INTERVAL; + in_dev->mr_qi =3D igmpv3_qqi(ih3) * HZ ? : IGMP_QUERY_INTERVAL; =20 /* RFC3376, 8.3. Query Response Interval: * The number of seconds represented by the [Query Response --=20 2.43.0