From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: passt.top; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=gb1LVGjE; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by passt.top (Postfix) with ESMTPS id 3938C5A061D for ; Mon, 24 Aug 2026 15:44:59 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1787579098; 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=aEH95Xa7egLxSyi3BZgcZZhvjYBlN8mEVohcT9mrpjY=; b=gb1LVGjEIY1AYhmcyudvRFXDnkXreGpic43frykMyJK3Mo+bcp4Q1DniRPQb2x9pNSMxPU EPbB3xOoC10rntJ8l45gvFhYfBEbm4Pja0ZqvftGVuOnvPiyr18DaxtHxcu9cVxUGv8FR7 fueMX9LTPYOme3BzNB9XMWgibzWoMSc= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-519-3PjvEwkKPAmBSMKuYmWEjQ-1; Mon, 24 Aug 2026 09:44:56 -0400 X-MC-Unique: 3PjvEwkKPAmBSMKuYmWEjQ-1 X-Mimecast-MFC-AGG-ID: 3PjvEwkKPAmBSMKuYmWEjQ_1787579095 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 50A8B195F179; Mon, 24 Aug 2026 13:44:55 +0000 (UTC) Received: from anskuma-thinkpadp1gen7.bengluru.csb (unknown [10.74.80.6]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 757FB1955F0F; Mon, 24 Aug 2026 13:44:51 +0000 (UTC) From: Anshu Kumari To: sbrivio@redhat.com, passt-dev@passt.top, anskuma@redhat.com Subject: [PATCH v6 2/6] dhcp: Add option state management with enum opt_state Date: Mon, 24 Aug 2026 19:14:30 +0530 Message-ID: <20260824134436.282300-3-anskuma@redhat.com> In-Reply-To: <20260824134436.282300-1-anskuma@redhat.com> References: <20260824134436.282300-1-anskuma@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: tIJQR7K8241r4eEt4kF3owUkorEKKtm1yIqJ2WN47Ww_1787579095 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true Message-ID-Hash: IWHMRU3Q5HV4S74ZM5RFB57G55UYGF3T X-Message-ID-Hash: IWHMRU3Q5HV4S74ZM5RFB57G55UYGF3T X-MailFrom: anskuma@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: david@gibson.dropbear.id.au, jmaloy@redhat.com, lvivier@redhat.com 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: Overloading slen = -1 to mean "not set" conflates the option length with its lifecycle state, and can't express additional states such as "set by the user via command-line" which will be needed for --dhcp-opt support. Introduce enum opt_state with OPT_UNSET (option not configured) and OPT_DEFAULT (derived from host configuration). Replace all slen = -1 / slen != -1 checks with state comparisons, and set state = OPT_DEFAULT for options initialised in dhcp_init() and at reply time in dhcp(). Link: https://bugs.passt.top/show_bug.cgi?id=192 Signed-off-by: Anshu Kumari --- v6: - Rewrote commit message to explain why slen = -1 overloading is problematic and how it motivates the enum. - Dropped explicit OPT_UNSET initialization loop inside dhcp_init(). - Realigned opts[51] initializer for consistency. v5: - New patch: introduce enum opt_state { OPT_UNSET, OPT_DEFAULT } to replace slen = -1 for tracking option state - Replace all slen = -1 / slen != -1 checks with state = OPT_UNSET / state != OPT_UNSET - Set OPT_DEFAULT for options initialised in dhcp_init() and at reply time --- dhcp.c | 58 ++++++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 38 insertions(+), 20 deletions(-) diff --git a/dhcp.c b/dhcp.c index bb72b72..321968a 100644 --- a/dhcp.c +++ b/dhcp.c @@ -33,13 +33,24 @@ #include "log.h" #include "dhcp.h" +/** + * enum opt_state - DHCP option state + * @OPT_UNSET: Option not configured + * @OPT_DEFAULT: Option derived from host configuration + */ +enum opt_state { + OPT_UNSET = 0, + OPT_DEFAULT, +}; + /** * struct opt - DHCP option * @sent: Convenience flag, set while filling replies - * @slen: Length of option defined for server, -1 if not going to be sent + * @slen: Length of option defined for server * @s: Option payload from server * @clen: Length of option received from client, -1 if not received * @c: Option payload from client + * @state: Option state (unset or default) */ struct opt { int sent; @@ -47,6 +58,7 @@ struct opt { uint8_t s[255]; int clen; uint8_t c[255]; + enum opt_state state; }; static struct opt opts[256]; @@ -73,19 +85,17 @@ static struct opt opts[256]; */ void dhcp_init(void) { - int i; - - for (i = 0; i < ARRAY_SIZE(opts); i++) - opts[i].slen = -1; - - opts[1] = (struct opt) { 0, 4, { 0 }, 0, { 0 }, }; /* Mask */ - opts[3] = (struct opt) { 0, 4, { 0 }, 0, { 0 }, }; /* Router */ - opts[51] = (struct opt) { 0, 4, { 0xff, - 0xff, - 0xff, - 0xff }, 0, { 0 }, }; /* Lease time */ - opts[53] = (struct opt) { 0, 1, { 0 }, 0, { 0 }, }; /* Type */ - opts[54] = (struct opt) { 0, 4, { 0 }, 0, { 0 }, }; /* Server ID */ + /* Mask */ + opts[1] = (struct opt) { 0, 4, { 0 }, 0, { 0 }, OPT_DEFAULT, }; + /* Router */ + opts[3] = (struct opt) { 0, 4, { 0 }, 0, { 0 }, OPT_DEFAULT, }; + /* Lease time */ + opts[51] = (struct opt) { 0, 4, { 0xff, 0xff, 0xff, 0xff }, + 0, { 0 }, OPT_DEFAULT }; + /* Type */ + opts[53] = (struct opt) { 0, 1, { 0 }, 0, { 0 }, OPT_DEFAULT, }; + /* Server ID */ + opts[54] = (struct opt) { 0, 4, { 0 }, 0, { 0 }, OPT_DEFAULT, }; } /** @@ -183,13 +193,13 @@ static int fill(struct msg *m) for (i = 0; i < opts[55].clen; i++) { o = opts[55].c[i]; - if (opts[o].slen != -1) + if (opts[o].state != OPT_UNSET) if (fill_one(m->o, OPT_MAX, o, &offset)) debug("DHCP: skipping option %i", o); } for (o = 0; o < 255; o++) { - if (opts[o].slen != -1 && !opts[o].sent) + if (opts[o].state != OPT_UNSET && !opts[o].sent) if (fill_one(m->o, OPT_MAX, o, &offset)) debug("DHCP: skipping option %i", o); } @@ -243,6 +253,7 @@ static void opt_set_dns_search(const struct ctx *c, size_t max_len) int i; opts[119].slen = 0; + opts[119].state = OPT_DEFAULT; for (i = 0; i < 255; i++) max_len -= opts[i].slen; @@ -291,7 +302,7 @@ static void opt_set_dns_search(const struct ctx *c, size_t max_len) } if (!opts[119].slen) - opts[119].slen = -1; + opts[119].state = OPT_UNSET; } /** @@ -389,7 +400,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data) iov_drop_header(data, *olen); } - opts[80].slen = -1; + opts[80].state = OPT_UNSET; if (opts[53].clen > 0 && opts[53].c[0] == DHCPDISCOVER) { if (opts[80].clen == -1) { info("DHCP: offer to discover"); @@ -398,6 +409,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data) info("DHCP: ack to discover (Rapid Commit)"); opts[53].s[0] = DHCPACK; opts[80].slen = 0; + opts[80].state = OPT_DEFAULT; } } else if (opts[53].clen <= 0 || opts[53].c[0] == DHCPREQUEST) { info("%s: ack to request", /* DHCP needs a valid message type */ @@ -421,6 +433,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data) != (c->ip4.guest_gw.s_addr & mask.s_addr)) { /* a.b.c.d/32:0.0.0.0, 0:a.b.c.d */ opts[121].slen = 14; + opts[121].state = OPT_DEFAULT; opts[121].s[0] = 32; memcpy(opts[121].s + 1, &c->ip4.guest_gw, sizeof(c->ip4.guest_gw)); @@ -430,6 +443,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data) if (c->mtu) { opts[26].slen = 2; + opts[26].state = OPT_DEFAULT; opts[26].s[0] = c->mtu / 256; opts[26].s[1] = c->mtu % 256; } @@ -441,12 +455,15 @@ int dhcp(const struct ctx *c, struct iov_tail *data) ((struct in_addr *)opts[6].s)[i] = c->ip4.dns[i]; opts[6].slen += sizeof(uint32_t); } - if (!opts[6].slen) - opts[6].slen = -1; + if (opts[6].slen) + opts[6].state = OPT_DEFAULT; + else + opts[6].state = OPT_UNSET; opt_len = strlen(c->hostname); if (opt_len > 0) { opts[12].slen = opt_len; + opts[12].state = OPT_DEFAULT; memcpy(opts[12].s, &c->hostname, opt_len); } @@ -463,6 +480,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data) encode_domain_name((char *)opts[81].s + 3, c->fqdn); opts[81].slen = opt_len; + opts[81].state = OPT_DEFAULT; } else { debug("DHCP: client FQDN option doesn't fit, skipping"); } -- 2.55.0