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[2a10:fc81:a806:d6a9::1]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-447f6f0556bsm236505095e9.12.2025.05.26.07.20.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 May 2025 07:20:42 -0700 (PDT) Date: Mon, 26 May 2025 16:20:41 +0200 From: Stefano Brivio To: Laurent Vivier Subject: Re: [PATCH v5 16/29] dhcpv6: Use iov_tail in dhcpv6_opt() Message-ID: <20250526162041.119d8951@elisabeth> In-Reply-To: <20250417165136.2688884-17-lvivier@redhat.com> References: <20250417165136.2688884-1-lvivier@redhat.com> <20250417165136.2688884-17-lvivier@redhat.com> Organization: Red Hat X-Mailer: Claws Mail 4.2.0 (GTK 3.24.49; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: scpt5XoIS8rOfZW2ZIrLFWeZafc2eH0_36hHijMyJPM_1748269243 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-ID-Hash: WATKGPOHAXAEF4IINWUOAAM4RTGHXL4L X-Message-ID-Hash: WATKGPOHAXAEF4IINWUOAAM4RTGHXL4L 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 Thu, 17 Apr 2025 18:51:23 +0200 Laurent Vivier wrote: > Signed-off-by: Laurent Vivier > --- > dhcpv6.c | 179 ++++++++++++++++++++++++++++++++----------------------- > iov.c | 1 - > 2 files changed, 103 insertions(+), 77 deletions(-) > > diff --git a/dhcpv6.c b/dhcpv6.c > index a52af1b7a0fe..365b609addda 100644 > --- a/dhcpv6.c > +++ b/dhcpv6.c > @@ -278,112 +278,122 @@ static struct resp_not_on_link_t { > > /** > * dhcpv6_opt() - Get option from DHCPv6 message > - * @p: Packet pool, single packet with UDP header > - * @offset: Offset to look at, 0: end of header, set to option start > + * @data: Data to look at (input/output) This isn't really clear to me. I'd rather say it's data where we look for options, and that it's set to the option on return, maybe: @data: Buffer with options, set to matching option on return ? > * @type: Option type to look up, network order > * > - * Return: pointer to option header, or NULL on malformed or missing option > + * Return: true if found and @data points to the option header, > + * or false on malformed or missing option and @data is > + * unmodified. > */ > -static struct opt_hdr *dhcpv6_opt(const struct pool *p, size_t *offset, > - uint16_t type) > +static bool dhcpv6_opt(struct iov_tail *data, uint16_t type) > { > - struct opt_hdr *o; > - size_t left; > + struct iov_tail head = *data; > + const struct opt_hdr *o; > + struct opt_hdr oc; > > - ASSERT(*offset >= UDP_MSG_HDR_SIZE); > - > - while ((o = packet_get_try(p, 0, *offset, sizeof(*o), &left))) { > + while ((o = IOV_PEEK_HEADER(data, oc))) { > unsigned int opt_len = ntohs(o->l) + sizeof(*o); > > - if (ntohs(o->l) > left) > - return NULL; > + if (opt_len > iov_tail_size(data)) > + break; > > if (o->t == type) > - return o; > + return true; > > - *offset += opt_len; > + iov_tail_drop(data, opt_len); > } > > - return NULL; > + *data = head; > + return false; > } > > /** > * dhcpv6_ia_notonlink() - Check if any IA contains non-appropriate addresses > - * @p: Packet pool, single packet starting from UDP header > + * @data: Data to look at, packet starting from UDP header (input/output) > * @la: Address we want to lease to the client > * > - * Return: pointer to non-appropriate IA_NA or IA_TA, if any, NULL otherwise > + * Return: true and @data points to non-appropriate IA_NA or IA_TA, if any, > + * false otherwise and @data is unmodified > */ > -static struct opt_hdr *dhcpv6_ia_notonlink(const struct pool *p, > - struct in6_addr *la) > +static bool dhcpv6_ia_notonlink(struct iov_tail *data, > + struct in6_addr *la) > { > int ia_types[2] = { OPT_IA_NA, OPT_IA_TA }, *ia_type; > const struct opt_ia_addr *opt_addr; > + struct iov_tail current, ia_base; > + struct opt_ia_addr opt_addrc; > char buf[INET6_ADDRSTRLEN]; > + const struct opt_ia_na *ia; > struct in6_addr req_addr; > const struct opt_hdr *h; > - struct opt_hdr *ia; > - size_t offset; > + struct opt_ia_na iac; > + struct opt_hdr hc; > > foreach(ia_type, ia_types) { > - offset = UDP_MSG_HDR_SIZE; > - while ((ia = dhcpv6_opt(p, &offset, *ia_type))) { > - if (ntohs(ia->l) < OPT_VSIZE(ia_na)) > - return NULL; > - > - offset += sizeof(struct opt_ia_na); > - > - while ((h = dhcpv6_opt(p, &offset, OPT_IAAADR))) { > - if (ntohs(h->l) != OPT_VSIZE(ia_addr)) > - return NULL; > - > - opt_addr = (const struct opt_ia_addr *)h; > + current = *data; > + while (dhcpv6_opt(¤t, *ia_type)) { > + ia_base = current; > + ia = IOV_REMOVE_HEADER(¤t, iac); > + if (!ia || ntohs(ia->hdr.l) < OPT_VSIZE(ia_na)) > + goto notfound; > + > + while (dhcpv6_opt(¤t, OPT_IAAADR)) { > + h = IOV_PEEK_HEADER(¤t, hc); > + if (!h || ntohs(h->l) != OPT_VSIZE(ia_addr)) > + goto notfound; > + > + opt_addr = IOV_REMOVE_HEADER(¤t, > + opt_addrc); > req_addr = opt_addr->addr; > if (!IN6_ARE_ADDR_EQUAL(la, &req_addr)) > - goto err; > - > - offset += sizeof(struct opt_ia_addr); > + goto notonlink; > } > } > } > > - return NULL; > +notfound: > + return false; > > -err: > +notonlink: > info("DHCPv6: requested address %s not on link", > inet_ntop(AF_INET6, &req_addr, buf, sizeof(buf))); > - return ia; > + *data = ia_base; > + return true; > } > > /** > * dhcpv6_send_ia_notonlink() - Send NotOnLink status > - * @c: Execution context > - * @ia: Pointer to non-appropriate IA_NA or IA_TA > - * @client_id: Client ID message option > - * xid: Transaction ID for message exchange > + * @c: Execution context > + * @ia_base: Non-appropriate IA_NA or IA_TA base > + * @client_id_base: Client ID message option base > + * @len: Client ID length > + * @xid: Transaction ID for message exchange > */ > -static void dhcpv6_send_ia_notonlink(struct ctx *c, struct opt_hdr *ia, > - const struct opt_hdr *client_id, > - uint32_t xid) > +static void dhcpv6_send_ia_notonlink(struct ctx *c, > + const struct iov_tail *ia_base, > + const struct iov_tail *client_id_base, > + int len, uint32_t xid) > { > const struct in6_addr *src = &c->ip6.our_tap_ll; > + struct opt_hdr *ia = (struct opt_hdr *)resp_not_on_link.var; > size_t n; > > info("DHCPv6: received CONFIRM with inappropriate IA," > " sending NotOnLink status in REPLY"); > > - ia->l = htons(OPT_VSIZE(ia_na) + sizeof(sc_not_on_link)); > - > n = sizeof(struct opt_ia_na); > - memcpy(resp_not_on_link.var, ia, n); > + iov_to_buf(&ia_base->iov[0], ia_base->cnt, ia_base->off, > + resp_not_on_link.var, n); > + ia->l = htons(OPT_VSIZE(ia_na) + sizeof(sc_not_on_link)); > memcpy(resp_not_on_link.var + n, &sc_not_on_link, > sizeof(sc_not_on_link)); > > n += sizeof(sc_not_on_link); > - memcpy(resp_not_on_link.var + n, client_id, > - sizeof(struct opt_hdr) + ntohs(client_id->l)); > + iov_to_buf(&client_id_base->iov[0], client_id_base->cnt, > + client_id_base->off, resp_not_on_link.var + n, > + sizeof(struct opt_hdr) + len); > > - n += sizeof(struct opt_hdr) + ntohs(client_id->l); > + n += sizeof(struct opt_hdr) + len; > > n = offsetof(struct resp_not_on_link_t, var) + n; > > @@ -472,17 +482,19 @@ search: > > /** > * dhcpv6_client_fqdn_fill() - Fill in client FQDN option > + * @data: Data to look at > * @c: Execution context > * @buf: Response message buffer where options will be appended > * @offset: Offset in message buffer for new options > * > * Return: updated length of response message buffer. > */ > -static size_t dhcpv6_client_fqdn_fill(const struct pool *p, const struct ctx *c, > +static size_t dhcpv6_client_fqdn_fill(const struct iov_tail *data, > + const struct ctx *c, > char *buf, int offset) > > { > - struct opt_client_fqdn const *req_opt; > + struct iov_tail current = *data; > struct opt_client_fqdn *o; > size_t opt_len; > > @@ -501,13 +513,16 @@ static size_t dhcpv6_client_fqdn_fill(const struct pool *p, const struct ctx *c, > > o = (struct opt_client_fqdn *)(buf + offset); > encode_domain_name(o->domain_name, c->fqdn); > - req_opt = (struct opt_client_fqdn *)dhcpv6_opt(p, > - &(size_t){ UDP_MSG_HDR_SIZE }, > - OPT_CLIENT_FQDN); > - if (req_opt && req_opt->flags & 0x01 /* S flag */) > - o->flags = 0x02 /* O flag */; > - else > - o->flags = 0x00; > + if (dhcpv6_opt(¤t, OPT_CLIENT_FQDN)) { > + struct opt_client_fqdn const *req_opt; > + struct opt_client_fqdn req_optc; > + > + req_opt = IOV_PEEK_HEADER(¤t, req_optc); > + if (req_opt && req_opt->flags & 0x01 /* S flag */) > + o->flags = 0x02 /* O flag */; > + else > + o->flags = 0x00; > + } Earlier, if we didn't find the option, we would set o->flags to 0x00. Now we do nothing. -- Stefano