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From: Enrique Llorente Pastora <ellorent@redhat.com>
To: Stefano Brivio <sbrivio@redhat.com>
Cc: passt-dev@passt.top
Subject: Re: [PATCH v5] dhcp, dhcpv6: Add hostname and client fqdn ops
Date: Thu, 2 Jan 2025 17:09:48 +0100	[thread overview]
Message-ID: <CAHVoYmLsEZEZApnoXc8ejGdjc_OJr-Mvi71kz=7mPXQ55VS=yw@mail.gmail.com> (raw)
In-Reply-To: <20250101225428.0f10934d@elisabeth>

On Wed, Jan 1, 2025 at 10:54 PM Stefano Brivio <sbrivio@redhat.com> wrote:
>
> On Thu, 19 Dec 2024 12:55:57 +0100
> Enrique Llorente <ellorent@redhat.com> wrote:
>
> > Both DHCPv4 and DHCPv6 has the capability to pass the hostname to
> > clients, the DHCPv4 uses option 12 (hostname) while the DHCPv6 uses option 39
> > (client fqdn), for some virt deployments like kubevirt is expected to
> > have the VirtualMachine name as the guest hostname.
> >
> > This change add the following arguments:
> >  - -H --hostname NAME to configure the hostname DHCPv4 option(12)
> >  - --fqdn NAME to configure client fqdn option for both DHCPv4(81) and
> >    DHCPv6(39)
> >
> > Signed-off-by: Enrique Llorente <ellorent@redhat.com>
> > ---
> >  conf.c           | 20 +++++++++++--
> >  dhcp.c           | 50 ++++++++++++++++++++++++++++----
> >  dhcpv6.c         | 75 +++++++++++++++++++++++++++++++++++++++---------
> >  passt.1          | 11 +++++++
> >  passt.h          |  5 ++++
> >  pasta.c          | 18 ++++++++----
> >  test/lib/setup   | 10 +++----
> >  test/passt.mbuto |  6 ++--
> >  test/passt/dhcp  | 15 +++++++++-
> >  util.c           | 23 +++++++++++++++
> >  util.h           |  6 ++++
> >  11 files changed, 204 insertions(+), 35 deletions(-)
> >
> > diff --git a/conf.c b/conf.c
> > index df2b016..5f21193 100644
> > --- a/conf.c
> > +++ b/conf.c
> > @@ -854,7 +854,9 @@ static void usage(const char *name, FILE *f, int status)
> >               FPRINTF(f, "    default: use addresses from /etc/resolv.conf\n");
> >       FPRINTF(f,
> >               "  -S, --search LIST    Space-separated list, search domains\n"
> > -             "    a single, empty option disables the DNS search list\n");
> > +             "    a single, empty option disables the DNS search list\n"
> > +             "  -H, --hostname NAME  Hostname to configure client with\n"
> > +             "  --fqdn NAME          FQDN to configure client with\n");
> >       if (strstr(name, "pasta"))
> >               FPRINTF(f, "    default: don't use any search list\n");
> >       else
> > @@ -1313,6 +1315,7 @@ void conf(struct ctx *c, int argc, char **argv)
> >               {"outbound",    required_argument,      NULL,           'o' },
> >               {"dns",         required_argument,      NULL,           'D' },
> >               {"search",      required_argument,      NULL,           'S' },
> > +             {"hostname",    required_argument,      NULL,           'H' },
> >               {"no-tcp",      no_argument,            &c->no_tcp,     1 },
> >               {"no-udp",      no_argument,            &c->no_udp,     1 },
> >               {"no-icmp",     no_argument,            &c->no_icmp,    1 },
> > @@ -1357,6 +1360,7 @@ void conf(struct ctx *c, int argc, char **argv)
> >               /* vhost-user backend program convention */
> >               {"print-capabilities", no_argument,     NULL,           26 },
> >               {"socket-path", required_argument,      NULL,           's' },
> > +             {"fqdn",        required_argument,      NULL,           27 },
> >               { 0 },
> >       };
> >       const char *logname = (c->mode == MODE_PASTA) ? "pasta" : "passt";
> > @@ -1379,9 +1383,9 @@ void conf(struct ctx *c, int argc, char **argv)
> >       if (c->mode == MODE_PASTA) {
> >               c->no_dhcp_dns = c->no_dhcp_dns_search = 1;
> >               fwd_default = FWD_AUTO;
> > -             optstring = "+dqfel:hF:I:p:P:m:a:n:M:g:i:o:D:S:46t:u:T:U:";
> > +             optstring = "+dqfel:hF:I:p:P:m:a:n:M:g:i:o:D:S:H:46t:u:T:U:";
> >       } else {
> > -             optstring = "+dqfel:hs:F:p:P:m:a:n:M:g:i:o:D:S:461t:u:";
> > +             optstring = "+dqfel:hs:F:p:P:m:a:n:M:g:i:o:D:S:H:461t:u:";
> >       }
> >
> >       c->tcp.fwd_in.mode = c->tcp.fwd_out.mode = FWD_UNSET;
> > @@ -1558,6 +1562,11 @@ void conf(struct ctx *c, int argc, char **argv)
> >               case 26:
> >                       vu_print_capabilities();
> >                       break;
> > +             case 27:
> > +                     if (snprintf_check(c->fqdn, PASST_MAXDNAME,
> > +                         "%s", optarg))
>
> Coding style: arguments are preferably aligned with parameter list they
> belong to:
>
>                         if (snprintf_check(c->fqdn, PASST_MAXDNAME,
>                                            "%s", optarg))
>
> for another example, look just 20 lines below this (case 's').
>

Done

> > +                             die("Invalid FQDN: %s", optarg);
> > +                     break;
> >               case 'd':
> >                       c->debug = 1;
> >                       c->quiet = 0;
> > @@ -1727,6 +1736,11 @@ void conf(struct ctx *c, int argc, char **argv)
> >
> >                       die("Cannot use DNS search domain %s", optarg);
> >                       break;
> > +             case 'H':
> > +                     if (snprintf_check(c->hostname, PASST_MAXDNAME,
> > +                         "%s", optarg))
>
> Same as above.
>

Done



> > +                             die("Invalid hostname: %s", optarg);
> > +                     break;
> >               case '4':
> >                       v4_only = true;
> >                       v6_only = false;
> > diff --git a/dhcp.c b/dhcp.c
> > index d8515aa..b224bf8 100644
> > --- a/dhcp.c
> > +++ b/dhcp.c
> > @@ -63,6 +63,12 @@ static struct opt opts[255];
> >
> >  #define OPT_MIN              60 /* RFC 951 */
> >
> > +/* 576 (RFC 2131), minus offset
> > + * of options (268), minus end
> > + * option and its length (2)
> > + */
>
> I formatted this multi-comment in my reply to v4 so that the first
> line would fit with the define:
>
> #define OPT_MAX         306     /* 576 (RFC 2131), minus offset ...
>
> but if you don't want to have it on the same line (no preference from my
> side), then there's no need for all that line wrapping (but then you
> should mention what it refers to), say:
>
> /* Total option size (excluding end option) is 576 (RFC 2131), minus
>  * offset of options (268), minus end option and its length (2).
>  */
> #define OPT_MAX         306
>

Will go with your multiline comment since it's quite large and it reads better.

> > +#define OPT_MAX              306
> > +
> >  /**
> >   * dhcp_init() - Initialise DHCP options
> >   */
> > @@ -122,7 +128,7 @@ struct msg {
> >       uint8_t sname[64];
> >       uint8_t file[128];
> >       uint32_t magic;
> > -     uint8_t o[308];
> > +     uint8_t o[OPT_MAX + 2]; /* End option and length */
>
> ..."plus end option and length", or move the comment so that it refers
> to the "2":
>
>         uint8_t o[OPT_MAX + 2 /* End option and its length */ ];
>
> Otherwise it looks like we use 310 bytes for the end option and its
> length.
>

Going with inlining it next to "2"

> >  } __attribute__((__packed__));
> >
> >  /**
> > @@ -130,15 +136,31 @@ struct msg {
> >   * @m:               Message to fill
> >   * @o:               Option number
> >   * @offset:  Current offset within options field, updated on insertion
> > + *
> > + * Return: offset for the next option field
> >   */
> > -static void fill_one(struct msg *m, int o, int *offset)
> > +static int fill_one(struct msg *m, int o, int *offset)
> >  {
> > +     size_t idx, slen = 0;
> > +
> > +     /* If it cannot write even enum + len + one byte, then just skip */
>
> ..."it" who? If we can't write, then skip.
>
> It's not clear what "enum" refers to, I guess that should be "number"
> or "code".
>

Done

> By the way, I just realised that this is not entirely correct because
> there's at least one option (option 80, "Rapid Commit") that has length
> zero (it's some sort of flag, with the presence of the option
> indicating that the feature is enabled).
>
> Maybe there's a more elegant solution to this, but a convenient
> alternative might be to check *offset + 1 /* length */ + !!slen instead.

Going with the alternative

>
> That's with slen assigned earlier, there's no point in initialising it
> to zero and then unconditionally reassigning it later.

Done

>
> > +     if (*offset + 2 > OPT_MAX)
> > +             return OPT_MAX;
> > +
> >       m->o[*offset] = o;
> >       m->o[*offset + 1] = opts[o].slen;
> > -     memcpy(&m->o[*offset + 2], opts[o].s, opts[o].slen);
> > +     idx = *offset + 2;
>
> I found it a bit difficult to understand what 'idx' is here (offset of
> option value). Perhaps you could just recycle *offset to keep track of
> the actual offset as we move in the buffer.
>
> That is, we just set two bytes starting from *offset, and now we can do:
>
>         *offset += 2;
>

It Makes sense since we just use "idx" everywhere after that so we can
recycle it without problem.

> > +     slen = opts[o].slen;
> > +
> > +     /* Truncate if it goes beyond OPT_MAX */
>
> Shouldn't we also report something via debug() in this case?
>

Done.

> > +     if (idx + slen > OPT_MAX)
> > +             slen = OPT_MAX - idx;
>
> I didn't check what happens with a zero-length option, but it looks okay
> to me. The (pending) change at:
>
>   https://github.com/AsahiLinux/muvm/pull/111
>
> uses option 80 ("Rapid Commit"). I can also give it a quick try later.
>

Thanks for checking, it would be awesome to have some kind of matrix
test for all these cases though, like starting passt per test with
specific arguments.

> > +
> > +     memcpy(&m->o[*offset + 2], opts[o].s, slen);
> >
> >       opts[o].sent = 1;
> >       *offset += 2 + opts[o].slen;
> > +     return *offset;
> >  }
> >
> >  /**
> > @@ -172,7 +194,10 @@ static int fill(struct msg *m)
> >
> >       for (o = 0; o < 255; o++) {
> >               if (opts[o].slen != -1 && !opts[o].sent)
> > -                     fill_one(m, o, &offset);
> > +                     if (fill_one(m, o, &offset) == OPT_MAX) {
> > +                             debug("DHCP: truncating after option %i", o);
>
> I think there's an off-by-one here: if the options exactly fit the
> maximum size, we'll warn, but no truncation will actually happen.
>

It will truncate since no more options will be included, this is not
the same as inter option truncate.

> Perhaps we should print messages directly in fill_one(), as we have a
> better detail of what's going on, there?
>

I prefer to log directly at the place where the action is happening
(skipping the rest of the options.

> > +                             break;
> > +                     }
> >       }
> >
> >       m->o[offset++] = 255;
> > @@ -285,7 +310,7 @@ static void opt_set_dns_search(const struct ctx *c, size_t max_len)
> >   */
> >  int dhcp(const struct ctx *c, const struct pool *p)
> >  {
> > -     size_t mlen, dlen, offset = 0, opt_len, opt_off = 0;
> > +     size_t mlen, dlen, offset = 0, opt_len, opt_off = 0, hostname_len = 0, fqdn_len = 0;
>
> You're assigning those unconditionally before using them, so there's no
> need to initialise them here (otherwise one might mistake them as a
> "counter" kind of thing).
>

Done.

> Please wrap to 80 columns when feasible:
>
>         size_t mlen, dlen, offset = 0, opt_len, opt_off = 0;
>         size_t hostname_len, fqdn_len;
>
> and by the way, you can probably recycle opt_len for those.
>

Sure, recycling.

> >       char macstr[ETH_ADDRSTRLEN];
> >       struct in_addr mask, dst;
> >       const struct ethhdr *eh;
> > @@ -398,6 +423,21 @@ int dhcp(const struct ctx *c, const struct pool *p)
> >       if (!opts[6].slen)
> >               opts[6].slen = -1;
> >
> > +     hostname_len = strlen(c->hostname);
> > +     if (hostname_len > 0) {
> > +             opts[12].slen = hostname_len;
> > +             memcpy(opts[12].s, &c->hostname, hostname_len);
> > +     }
> > +
> > +     fqdn_len = strlen(c->fqdn);
> > +     if (fqdn_len > 0) {
> > +             size_t encoded_len = 0;
>
> Sorry, I missed a couple of observations on v4: encoded_len is
> uselessly initialised here, and RFC 4702, 2.2, says, about the RCODE
> fields:
>
>    A server SHOULD set these to 255 when sending the option
>    and MUST ignore them on receipt.
>
> but you're leaving them as zeroes here.

Done.

>
> > +             opts[81].s[0] = 0x4; /* flags (E) */
> > +             encoded_len = encode_domain_name(c->fqdn, fqdn_len,
> > +                                                     (char *) opts[81].s + 3);
>
> Arguments should be visually aligned:
>
>                 encoded_len = encode_domain_name(c->fqdn, fqdn_len,
>                                                  (char *)opts[81].s + 3);
>
> By the way, it's more common to have the destination buffer as first
> argument (see memcpy(), snprintf()).
>
> This usage would be more idiomatic and obvious (matching memcpy()) with
> something like:
>
>         encode_domain_name(opts[81].s + 3, c->fqdn, fqdn_len);
>

Done.

> > +             opts[81].slen = encoded_len + 3;
> > +     }
> > +
> >       if (!c->no_dhcp_dns_search)
> >               opt_set_dns_search(c, sizeof(m->o));
> >
> > diff --git a/dhcpv6.c b/dhcpv6.c
> > index 0523bba..ce3a1bd 100644
> > --- a/dhcpv6.c
> > +++ b/dhcpv6.c
> > @@ -48,6 +48,7 @@ struct opt_hdr {
> >  # define  STATUS_NOTONLINK   htons_constant(4)
> >  # define OPT_DNS_SERVERS     htons_constant(23)
> >  # define OPT_DNS_SEARCH              htons_constant(24)
> > +# define OPT_CLIENT_FQDN     htons_constant(39)
> >  #define   STR_NOTONLINK              "Prefix not appropriate for link."
> >
> >       uint16_t l;
> > @@ -58,6 +59,9 @@ struct opt_hdr {
> >                                             sizeof(struct opt_hdr))
> >  #define OPT_VSIZE(x)         (sizeof(struct opt_##x) -               \
> >                                sizeof(struct opt_hdr))
> > +#define OPT_MAX_SIZE         IPV6_MIN_MTU - (sizeof(struct ipv6hdr) + \
> > +                                             sizeof(struct udphdr) + \
> > +                                             sizeof(struct msg_hdr))
>
> You can just use tabs, no need to mix them with spaces here.
>

Done

> >
> >  /**
> >   * struct opt_client_id - DHCPv6 Client Identifier option
> > @@ -163,6 +167,18 @@ struct opt_dns_search {
> >       char list[MAXDNSRCH * NS_MAXDNAME];
> >  } __attribute__((packed));
> >
> > +/**
> > + * struct opt_client_fqdn - Client FQDN option (RFC 4704)
> > + * @hdr:             Option header
> > + * @flags:           Flags described by RFC 4704 (always zero for us)
> > + * @domain_name:     Client FQDN
> > + */
> > +struct opt_client_fqdn{
>
> Missing space between identifier and {.
>

Done

> > +     struct opt_hdr hdr;
> > +     uint8_t flags;
> > +     char domain_name[PASST_MAXDNAME];
> > +} __attribute__((packed));
> > +
> >  /**
> >   * struct msg_hdr - DHCPv6 client/server message header
> >   * @type:            DHCP message type
> > @@ -193,6 +209,7 @@ struct msg_hdr {
> >   * @client_id:               Client Identifier, variable length
> >   * @dns_servers:     DNS Recursive Name Server, here just for storage size
> >   * @dns_search:              Domain Search List, here just for storage size
> > + * @client_fqdn:     Client FQDN, variable length
> >   */
> >  static struct resp_t {
> >       struct msg_hdr hdr;
> > @@ -203,6 +220,7 @@ static struct resp_t {
> >       struct opt_client_id client_id;
> >       struct opt_dns_servers dns_servers;
> >       struct opt_dns_search dns_search;
> > +     struct opt_client_fqdn client_fqdn;
> >  } __attribute__((__packed__)) resp = {
> >       { 0 },
> >       SERVER_ID,
> > @@ -228,6 +246,10 @@ static struct resp_t {
> >       { { OPT_DNS_SEARCH,     0, },
> >         { 0 },
> >       },
> > +
> > +     { { OPT_CLIENT_FQDN, 0, },
> > +       0, { 0 },
> > +     },
> >  };
> >
> >  static const struct opt_status_code sc_not_on_link = {
> > @@ -346,7 +368,6 @@ static size_t dhcpv6_dns_fill(const struct ctx *c, char *buf, int offset)
> >  {
> >       struct opt_dns_servers *srv = NULL;
> >       struct opt_dns_search *srch = NULL;
> > -     char *p = NULL;
> >       int i;
> >
> >       if (c->no_dhcp_dns)
> > @@ -373,6 +394,7 @@ search:
> >               return offset;
> >
> >       for (i = 0; *c->dns_search[i].n; i++) {
> > +             size_t encoded_name_len = 0;
> >               size_t name_len = strlen(c->dns_search[i].n);
> >
> >               /* We already append separators, don't duplicate if present */
> > @@ -388,29 +410,53 @@ search:
> >                       offset += sizeof(struct opt_hdr);
> >                       srch->hdr.t = OPT_DNS_SEARCH;
> >                       srch->hdr.l = 0;
> > -                     p = srch->list;
> >               }
> > -
> > -             *p = '.';
> > -             p = stpncpy(p + 1, c->dns_search[i].n, name_len);
> > -             p++;
> > -             srch->hdr.l += name_len + 2;
> > -             offset += name_len + 2;
> > +
> > +             encoded_name_len = encode_domain_name(c->dns_search[i].n,
> > +                                name_len, srch->list);
>
> Please align these arguments:
>
>                 encoded_name_len = encode_domain_name(c->dns_search[i].n,
>                                                       name_len, srch->list);
>

Done.

> > +             srch->hdr.l += encoded_name_len;
> > +             offset += encoded_name_len;
> >       }
> >
> >       if (srch) {
>
> There's no need for those curly brackets anymore.
>

Done.

> > -             for (i = 0; i < srch->hdr.l; i++) {
> > -                     if (srch->list[i] == '.') {
> > -                             srch->list[i] = strcspn(srch->list + i + 1,
> > -                                                     ".");
> > -                     }
> > -             }
> >               srch->hdr.l = htons(srch->hdr.l);
> >       }
> >
> >       return offset;
> >  }
> >
> > +/**
> > + * dhcpv6_client_fqdn_fill() - Fill in client FQDN option
> > + * @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 ctx *c, char *buf, int offset)
>
> Wrap to 80 columns:
>
> static size_t dhcpv6_client_fqdn_fill(const struct ctx *c, char *buf,
>                                       int offset)
>

Done.

> > +{
> > +     size_t fqdn_len, opt_hdr_len, opt_len, encoded_fqdn_len;
> > +     struct opt_client_fqdn *o;
> > +
> > +     opt_hdr_len = sizeof(struct opt_hdr);
>
> Does this really need its own variable?
>

Not really, removing.


> > +
> > +     fqdn_len = MIN(strlen(c->fqdn), OPT_MAX_SIZE - (offset + opt_hdr_len + 1));
>
> Wrap to 80 columns. This isn't really clear: here you seem to be using
> it as maximum length for the option, but then encode_domain_name()
> doesn't use it like that (it's the "Domain name length" according to
> the comment there).
>

I am going to re-use "opt_len" for all of this, no need for a new
variable, if this is the issue.

> > +
>
> Stray tab.
>

Done.

> > +     if (fqdn_len == 0)
>
> What if it's negative? I guess you should use ssize_t for fqdn_len, and
> adjust the check here.
>

Done

> > +             return offset;
> > +
> > +     o = (struct opt_client_fqdn *)(buf + offset);
> > +     encoded_fqdn_len = encode_domain_name(c->fqdn, fqdn_len,
> > +                                                     o->domain_name);
>
> Argument alignment:
>
>         encoded_fqdn_len = encode_domain_name(c->fqdn, fqdn_len,
>                                               o->domain_name);
>
> I don't understand: if the option is too long, where is it truncated?
>

The len after truncate it is already calculated so passing it to
"encode_domain_name" will truncate the c->fqdn value.

> > +     opt_len = encoded_fqdn_len + 1;
> > +
> > +     o->hdr.t = OPT_CLIENT_FQDN;
> > +     o->hdr.l = htons(opt_len);
> > +     o->flags = 0x00;
>
> I guess I mentioned this already: given that we'll set the "S" bit to
> zero (which is correct), if the client's value for the "S" bit is not
> zero, we'll need to set the "O" bit.
>

Totally forgotten, done.

> > +
> > +     return offset + opt_hdr_len + opt_len;
> > +}
> > +
> >  /**
> >   * dhcpv6() - Check if this is a DHCPv6 message, reply as needed
> >   * @c:               Execution context
> > @@ -544,6 +590,7 @@ int dhcpv6(struct ctx *c, const struct pool *p,
> >       n = offsetof(struct resp_t, client_id) +
> >           sizeof(struct opt_hdr) + ntohs(client_id->l);
> >       n = dhcpv6_dns_fill(c, (char *)&resp, n);
> > +     n = dhcpv6_client_fqdn_fill(c, (char *)&resp, n);
> >
> >       resp.hdr.xid = mh->xid;
> >
> > diff --git a/passt.1 b/passt.1
> > index d9cd33e..8f6b194 100644
> > --- a/passt.1
> > +++ b/passt.1
> > @@ -401,6 +401,17 @@ Enable IPv6-only operation. IPv4 traffic will be ignored.
> >  By default, IPv4 operation is enabled as long as at least an IPv4 route and an
> >  interface address are configured on a given host interface.
> >
> > +.TP
> > +.BR \-H ", " \-\-hostname " " \fIname
> > +Hostname to configure client with.
>
> For consistency: "the client".
>

Done.

> > +Send \fIname as DHCP option 12 (hostname).
>
> I think you want to have "name" in italic, not the whole rest of line
> (\fIname\fR). Have a look at the result with 'man ./passt.1'.
>

Done.

> > +
> > +.TP
> > +.BR \-\-fqdn " " \fIname
> > +FQDN to configure client with.
> > +Send \fIname as dhcp client fqdn option, for DHCP option 81 and for
>
> Same as above.
>

Done

> It's "DHCP" and "FQDN".
>

What do you mean ?

> > +DHCPv6 option 39.
> > +
> >  .SS \fBpasst\fR-only options
> >
> >  .TP
> > diff --git a/passt.h b/passt.h
> > index 0dd4efa..9909a10 100644
> > --- a/passt.h
> > +++ b/passt.h
> > @@ -209,6 +209,8 @@ struct ip6_ctx {
> >   * @ifi4:            Template interface for IPv4, -1: none, 0: IPv4 disabled
> >   * @ip:                      IPv4 configuration
> >   * @dns_search:              DNS search list
> > + * @hostname:                Guest hostname
> > + * @fqdn:            Guest FQDN
> >   * @ifi6:            Template interface for IPv6, -1: none, 0: IPv6 disabled
> >   * @ip6:             IPv6 configuration
> >   * @pasta_ifn:               Name of namespace interface for pasta
> > @@ -268,6 +270,9 @@ struct ctx {
> >       struct ip4_ctx ip4;
> >
> >       struct fqdn dns_search[MAXDNSRCH];
> > +
> > +    char hostname[PASST_MAXDNAME];
> > +    char fqdn[PASST_MAXDNAME];
>
> Indent with one tab, not spaces.
>

Done.

> >
> >       int ifi6;
> >       struct ip6_ctx ip6;
> > diff --git a/pasta.c b/pasta.c
> > index ff41c95..00678f3 100644
> > --- a/pasta.c
> > +++ b/pasta.c
> > @@ -173,6 +173,7 @@ void pasta_open_ns(struct ctx *c, const char *netns)
> >  struct pasta_spawn_cmd_arg {
> >       const char *exe;
> >       char *const *argv;
> > +     struct ctx *c;
>
> The struct comment should be updated as a result.
>

Done.

> >  };
> >
> >  /**
> > @@ -186,6 +187,7 @@ static int pasta_spawn_cmd(void *arg)
> >  {
> >       char hostname[HOST_NAME_MAX + 1] = HOSTNAME_PREFIX;
> >       const struct pasta_spawn_cmd_arg *a;
> > +     size_t conf_hostname_len;
> >       sigset_t set;
> >
> >       /* We run in a detached PID and mount namespace: mount /proc over */
> > @@ -194,10 +196,16 @@ static int pasta_spawn_cmd(void *arg)
> >
> >       if (write_file("/proc/sys/net/ipv4/ping_group_range", "0 0"))
> >               warn("Cannot set ping_group_range, ICMP requests might fail");
> > -
> > -     if (!gethostname(hostname + sizeof(HOSTNAME_PREFIX) - 1,
> > -                      HOST_NAME_MAX + 1 - sizeof(HOSTNAME_PREFIX)) ||
> > -         errno == ENAMETOOLONG) {
> > +
>
> Stray tab.
>
> > +     a = (const struct pasta_spawn_cmd_arg *)arg;
> > +
> > +     conf_hostname_len = strlen(a->c->hostname);
> > +     if (conf_hostname_len > 0) {
> > +             if (sethostname(a->c->hostname, conf_hostname_len))
> > +                     warn("Unable to set configured hostname");
> > +     }else if (!gethostname(hostname + sizeof(HOSTNAME_PREFIX) - 1,
>
> Missing space between } and else.
>

Done.

> > +                HOST_NAME_MAX + 1 - sizeof(HOSTNAME_PREFIX)) ||
>
> This is an argument to gethostname(), so it should be aligned
> accordingly.
>

Done

> > +           errno == ENAMETOOLONG) {
>
> This is now aligned under "if" for some reason, instead of the original
> (correct) alignment after "(".
>

Done.

> >               hostname[HOST_NAME_MAX] = '\0';
> >               if (sethostname(hostname, strlen(hostname)))
> >                       warn("Unable to set pasta-prefixed hostname");
> > @@ -208,7 +216,6 @@ static int pasta_spawn_cmd(void *arg)
> >       sigaddset(&set, SIGUSR1);
> >       sigwaitinfo(&set, NULL);
> >
> > -     a = (const struct pasta_spawn_cmd_arg *)arg;
> >       execvp(a->exe, a->argv);
> >
> >       die_perror("Failed to start command or shell");
> > @@ -230,6 +237,7 @@ void pasta_start_ns(struct ctx *c, uid_t uid, gid_t gid,
> >       struct pasta_spawn_cmd_arg arg = {
> >               .exe = argv[0],
> >               .argv = argv,
> > +             .c = c,
> >       };
> >       char uidmap[BUFSIZ], gidmap[BUFSIZ];
> >       char *sh_argv[] = { NULL, NULL };
> > diff --git a/test/lib/setup b/test/lib/setup
> > index 580825f..ee67152 100755
> > --- a/test/lib/setup
> > +++ b/test/lib/setup
> > @@ -49,7 +49,7 @@ setup_passt() {
> >
> >       context_run passt "make clean"
> >       context_run passt "make valgrind"
> > -     context_run_bg passt "valgrind --max-stackframe=$((4 * 1024 * 1024)) --trace-children=yes --vgdb=no --error-exitcode=1 --suppressions=test/valgrind.supp ./passt ${__opts} -s ${STATESETUP}/passt.socket -f -t 10001 -u 10001 -P ${STATESETUP}/passt.pid"
> > +     context_run_bg passt "valgrind --max-stackframe=$((4 * 1024 * 1024)) --trace-children=yes --vgdb=no --error-exitcode=1 --suppressions=test/valgrind.supp ./passt ${__opts} -s ${STATESETUP}/passt.socket -f -t 10001 -u 10001 -H hostname1 --fqdn fqdn1.passt.test -P ${STATESETUP}/passt.pid"
> >
> >       # pidfile isn't created until passt is listening
> >       wait_for [ -f "${STATESETUP}/passt.pid" ]
> > @@ -160,11 +160,11 @@ setup_passt_in_ns() {
> >       if [ ${VALGRIND} -eq 1 ]; then
> >               context_run passt "make clean"
> >               context_run passt "make valgrind"
> > -             context_run_bg passt "valgrind --max-stackframe=$((4 * 1024 * 1024)) --trace-children=yes --vgdb=no --error-exitcode=1 --suppressions=test/valgrind.supp ./passt -f ${__opts} -s ${STATESETUP}/passt.socket -t 10001,10011,10021,10031 -u 10001,10011,10021,10031 -P ${STATESETUP}/passt.pid --map-host-loopback ${__map_ns4} --map-host-loopback ${__map_ns6}"
> > +             context_run_bg passt "valgrind --max-stackframe=$((4 * 1024 * 1024)) --trace-children=yes --vgdb=no --error-exitcode=1 --suppressions=test/valgrind.supp ./passt -f ${__opts} -s ${STATESETUP}/passt.socket -H hostname1 --fqdn fqdn1.passt.test -t 10001,10011,10021,10031 -u 10001,10011,10021,10031 -P ${STATESETUP}/passt.pid --map-host-loopback ${__map_ns4} --map-host-loopback ${__map_ns6}"
> >       else
> >               context_run passt "make clean"
> >               context_run passt "make"
> > -             context_run_bg passt "./passt -f ${__opts} -s ${STATESETUP}/passt.socket -t 10001,10011,10021,10031 -u 10001,10011,10021,10031 -P ${STATESETUP}/passt.pid --map-host-loopback ${__map_ns4} --map-host-loopback ${__map_ns6}"
> > +             context_run_bg passt "./passt -f ${__opts} -s ${STATESETUP}/passt.socket -H hostname1 --fqdn fqdn1.passt.test -t 10001,10011,10021,10031 -u 10001,10011,10021,10031 -P ${STATESETUP}/passt.pid --map-host-loopback ${__map_ns4} --map-host-loopback ${__map_ns6}"
> >       fi
> >       wait_for [ -f "${STATESETUP}/passt.pid" ]
> >
> > @@ -243,7 +243,7 @@ setup_two_guests() {
> >       [ ${TRACE} -eq 1 ] && __opts="${__opts} --trace"
> >       [ ${VHOST_USER} -eq 1 ] && __opts="${__opts} --vhost-user"
> >
> > -     context_run_bg passt_1 "./passt -s ${STATESETUP}/passt_1.socket -P ${STATESETUP}/passt_1.pid -f ${__opts} -t 10001 -u 10001"
> > +     context_run_bg passt_1 "./passt -s ${STATESETUP}/passt_1.socket -P ${STATESETUP}/passt_1.pid -f ${__opts} --fqdn fqdn1.passt.test -H hostname1 -t 10001 -u 10001"
> >       wait_for [ -f "${STATESETUP}/passt_1.pid" ]
> >
> >       __opts=
> > @@ -252,7 +252,7 @@ setup_two_guests() {
> >       [ ${TRACE} -eq 1 ] && __opts="${__opts} --trace"
> >       [ ${VHOST_USER} -eq 1 ] && __opts="${__opts} --vhost-user"
> >
> > -     context_run_bg passt_2 "./passt -s ${STATESETUP}/passt_2.socket -P ${STATESETUP}/passt_2.pid -f ${__opts} -t 10004 -u 10004"
> > +     context_run_bg passt_2 "./passt -s ${STATESETUP}/passt_2.socket -P ${STATESETUP}/passt_2.pid -f ${__opts} --hostname hostname2 --fqdn fqdn2 -t 10004 -u 10004"
> >       wait_for [ -f "${STATESETUP}/passt_2.pid" ]
> >
> >       __vmem="$((${MEM_KIB} / 1024 / 4))"
> > diff --git a/test/passt.mbuto b/test/passt.mbuto
> > index 138d365..1e07693 100755
> > --- a/test/passt.mbuto
> > +++ b/test/passt.mbuto
> > @@ -13,7 +13,7 @@
> >  PROGS="${PROGS:-ash,dash,bash ip mount ls insmod mkdir ln cat chmod lsmod
> >         modprobe find grep mknod mv rm umount jq iperf3 dhclient hostname
> >         sed tr chown sipcalc cut socat dd strace ping tail killall sleep sysctl
> > -       nproc tcp_rr tcp_crr udp_rr which tee seq bc sshd ssh-keygen cmp}"
> > +       nproc tcp_rr tcp_crr udp_rr which tee seq bc sshd ssh-keygen cmp env}"
> >
> >  # OpenSSH 9.8 introduced split binaries, with sshd being the daemon, and
> >  # sshd-session the per-session program. We need the latter as well, and the path
> > @@ -41,6 +41,7 @@ FIXUP="${FIXUP}"'
> >  #!/bin/sh
> >  LOG=/var/log/dhclient-script.log
> >  echo \${reason} \${interface} >> \$LOG
> > +env >> \$LOG
> >  set >> \$LOG
> >
> >  [ -n "\${new_interface_mtu}" ]       && ip link set dev \${interface} mtu \${new_interface_mtu}
> > @@ -54,7 +55,8 @@ set >> \$LOG
> >  [ -n "\${new_ip6_address}" ]         && ip addr add \${new_ip6_address}/\${new_ip6_prefixlen} dev \${interface}
> >  [ -n "\${new_dhcp6_name_servers}" ]  && for d in \${new_dhcp6_name_servers}; do echo "nameserver \${d}%\${interface}" >> /etc/resolv.conf; done
> >  [ -n "\${new_dhcp6_domain_search}" ] && (printf "search"; for d in \${new_dhcp6_domain_search}; do printf " %s" "\${d}"; done; printf "\n") >> /etc/resolv.conf
> > -[ -n "\${new_host_name}" ]           && hostname "\${new_host_name}"
> > +[ -n "\${new_host_name}" ]           && echo "\${new_host_name}" > /tmp/new_host_name
> > +[ -n "\${new_fqdn_fqdn}" ]           && echo "\${new_fqdn_fqdn}" > /tmp/new_fqdn_fqdn
> >  exit 0
> >  EOF
> >       chmod 755 /sbin/dhclient-script
> > diff --git a/test/passt/dhcp b/test/passt/dhcp
> > index 9925ab9..145f1ba 100644
> > --- a/test/passt/dhcp
> > +++ b/test/passt/dhcp
> > @@ -11,7 +11,7 @@
> >  # Copyright (c) 2021 Red Hat GmbH
> >  # Author: Stefano Brivio <sbrivio@redhat.com>
> >
> > -gtools       ip jq dhclient sed tr
> > +gtools       ip jq dhclient sed tr hostname
> >  htools       ip jq sed tr head
> >
> >  test Interface name
> > @@ -47,7 +47,16 @@ gout       SEARCH sed 's/\. / /g' /etc/resolv.conf | sed 's/\.$//g' | sed -n 's/^searc
> >  hout HOST_SEARCH sed 's/\. / /g' /etc/resolv.conf | sed 's/\.$//g' | sed -n 's/^search \(.*\)/\1/p' | tr ' \n' ',' | sed 's/,$//;s/$/\n/'
> >  check        [ "__SEARCH__" = "__HOST_SEARCH__" ]
> >
> > +test DHCP: Hostname
> > +gout NEW_HOST_NAME cat /tmp/new_host_name
> > +check        [ "__NEW_HOST_NAME__" = "hostname1" ]
> > +
> > +test DHCP: Client FQDN
> > +gout NEW_FQDN_FQDN cat /tmp/new_fqdn_fqdn
> > +check        [ "__NEW_FQDN_FQDN__" = "fqdn1.passt.test" ]
> > +
> >  test DHCPv6: address
> > +guest        rm /tmp/new_fqdn_fqdn
> >  guest        /sbin/dhclient -6 __IFNAME__
> >  # Wait for DAD to complete
> >  guest        while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
> > @@ -70,3 +79,7 @@ test        DHCPv6: search list
> >  gout SEARCH6 sed 's/\. / /g' /etc/resolv.conf | sed 's/\.$//g' | sed -n 's/^search \(.*\)/\1/p' | tr ' \n' ',' | sed 's/,$//;s/$/\n/'
> >  hout HOST_SEARCH6 sed 's/\. / /g' /etc/resolv.conf | sed 's/\.$//g' | sed -n 's/^search \(.*\)/\1/p' | tr ' \n' ',' | sed 's/,$//;s/$/\n/'
> >  check        [ "__SEARCH6__" = "__HOST_SEARCH6__" ]
> > +
> > +test DHCPv6: Hostname
> > +gout NEW_FQDN_FQDN cat /tmp/new_fqdn_fqdn
> > +check        [ "__NEW_FQDN_FQDN__" = "fqdn1.passt.test" ]
> > diff --git a/util.c b/util.c
> > index 11973c4..7aeb5b4 100644
> > --- a/util.c
> > +++ b/util.c
> > @@ -837,3 +837,26 @@ void raw_random(void *buf, size_t buflen)
> >       if (random_read < buflen)
> >               die("Unexpected EOF on random data source");
> >  }
> > +/**
> > + * encode_domain_name() - Encode domain name according to RFC 1035, section 3.1
> > + * @domain_name:     Input domain name to encode
> > + * @len:     Domain name length
>
>
>
> > + * @buf:     Buffer to fill in with encoded domain name
>
> The descriptions should be aligned in the same way.

Done.

>
> Shouldn't the maximum buffer length to write be also specified?
>

What do you mean ?

> > + *
> > + * Return: encoded domain name length
> > + */
> > +size_t encode_domain_name(const char *domain_name, size_t len, char *buf)
> > +{
> > +     char *p;
> > +     size_t i;
>
> Please order these from longest to shortest.
>

Done.

> > +
> > +     buf[0] = strcspn(domain_name, ".");
> > +     p = buf + 1;
> > +     for (i = 0; i < len; i++) {
> > +             if (domain_name[i] == '.')
> > +                     p[i] = strcspn(domain_name + i + 1, ".");
> > +             else
> > +                     p[i] = domain_name[i];
> > +     }
> > +     return len + 2;
>
> This is +2 if we append a terminator byte at the end, which we should
> do as it's part of the encoding, but I don't see it being done.
>

Added it.

> > +}
> > diff --git a/util.h b/util.h
> > index 3fa1d12..c55ef29 100644
> > --- a/util.h
> > +++ b/util.h
> > @@ -40,6 +40,9 @@
> >  #ifndef IP_MAX_MTU
> >  #define IP_MAX_MTU                   USHRT_MAX
> >  #endif
> > +#ifndef IPV6_MIN_MTU
> > +#define IPV6_MIN_MTU        1280
> > +#endif
> >
> >  #ifndef MIN
> >  #define MIN(x, y)            (((x) < (y)) ? (x) : (y))
> > @@ -346,4 +349,7 @@ static inline int wrap_accept4(int sockfd, struct sockaddr *addr,
> >  #define accept4(s, addr, addrlen, flags) \
> >       wrap_accept4((s), (addr), (addrlen), (flags))
> >
> > +#define PASST_MAXDNAME 253 /* RFC 1035 */
> > +size_t encode_domain_name(const char* domain_name, size_t len, char* buf);
>
> For consistency: char *domain_name, char *buf
>
> > +
> >  #endif /* UTIL_H */
>
> --
> Stefano
>


--
Quique Llorente

CNV networking Senior Software Engineer

Red Hat EMEA

ellorent@redhat.com

@RedHat   Red Hat  Red Hat


  reply	other threads:[~2025-01-02 16:10 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-19 11:55 [PATCH v5] dhcp, dhcpv6: Add hostname and client fqdn ops Enrique Llorente
2025-01-01 21:54 ` Stefano Brivio
2025-01-02 16:09   ` Enrique Llorente Pastora [this message]
2025-01-02 22:00     ` Stefano Brivio

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