* [PATCH v2] dhcp, dhcpv6: Add hostname and client fqdn ops
@ 2024-11-14 8:47 Enrique Llorente
2024-11-14 17:13 ` Stefano Brivio
0 siblings, 1 reply; 4+ messages in thread
From: Enrique Llorente @ 2024-11-14 8:47 UTC (permalink / raw)
To: passt-dev; +Cc: Enrique Llorente
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 -H --hostname to configure the DHCPv4 and DHCPv6
options to will send hostname to clients.
Signed-off-by: Enrique Llorente <ellorent@redhat.com>
---
conf.c | 13 ++++++++++---
dhcp.c | 8 +++++++-
dhcpv6.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
passt.h | 2 ++
test/lib/setup | 10 +++++-----
test/passt.mbuto | 1 +
test/passt/dhcp | 11 ++++++++++-
7 files changed, 78 insertions(+), 11 deletions(-)
diff --git a/conf.c b/conf.c
index 14411b4..ddb585c 100644
--- a/conf.c
+++ b/conf.c
@@ -847,7 +847,8 @@ static void usage(const char *name, FILE *f, int status)
" --freebind Bind to any address for forwarding\n"
" --no-map-gw Don't map gateway address to host\n"
" -4, --ipv4-only Enable IPv4 operation only\n"
- " -6, --ipv6-only Enable IPv6 operation only\n");
+ " -6, --ipv6-only Enable IPv6 operation only\n"
+ " -H, --hostname NAME Hostname to configure client with\n");
if (strstr(name, "pasta"))
goto pasta_opts;
@@ -1303,6 +1304,7 @@ void conf(struct ctx *c, int argc, char **argv)
{"map-guest-addr", required_argument, NULL, 22 },
{"host-lo-to-ns-lo", no_argument, NULL, 23 },
{"dns-host", required_argument, NULL, 24 },
+ {"hostname", required_argument, NULL, 'H' },
{ 0 },
};
const char *logname = (c->mode == MODE_PASTA) ? "pasta" : "passt";
@@ -1325,9 +1327,9 @@ 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:46t:u:T:U:H:";
} 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:461t:u:H:";
}
c->tcp.fwd_in.mode = c->tcp.fwd_out.mode = FWD_UNSET;
@@ -1680,6 +1682,11 @@ void conf(struct ctx *c, int argc, char **argv)
c->one_off = true;
break;
+ case 'H':
+ ret = snprintf(c->hostname.n, sizeof(c->hostname.n), "%s", optarg);
+ if (ret <= 0 || ret >= (int)sizeof(c->hostname.n))
+ die("Invalid hostname: %s", optarg);
+ break;
case 't':
case 'u':
case 'T':
diff --git a/dhcp.c b/dhcp.c
index a06f143..ec7e78a 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -275,7 +275,7 @@ 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;
char macstr[ETH_ADDRSTRLEN];
const struct ethhdr *eh;
const struct iphdr *iph;
@@ -375,6 +375,12 @@ int dhcp(const struct ctx *c, const struct pool *p)
opts[6].slen += sizeof(uint32_t);
}
+ hostname_len = strlen(c->hostname.n);
+ if ( hostname_len > 0 ) {
+ opts[12].slen = hostname_len;
+ memcpy(opts[12].s, &c->hostname.n, hostname_len);
+ }
+
if (!c->no_dhcp_dns_search)
opt_set_dns_search(c, sizeof(m->o));
diff --git a/dhcpv6.c b/dhcpv6.c
index 14a5c7e..190dc0e 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;
@@ -163,6 +164,18 @@ 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 as stated at RFC 4704
+ * @hostname: Client fqdn
+ */
+struct opt_client_fqdn{
+ struct opt_hdr hdr;
+ uint8_t flags;
+ uint8_t hostname[NS_MAXDNAME];
+} __attribute__((packed));
+
/**
* struct msg_hdr - DHCPv6 client/server message header
* @type: DHCP message type
@@ -191,6 +204,7 @@ struct msg_hdr {
* @ia_na: Non-temporary Address option
* @ia_addr: Address for IA_NA
* @client_id: Client Identifier, variable length
+ * @client_fqdn: Client FQDN, variable length
* @dns_servers: DNS Recursive Name Server, here just for storage size
* @dns_search: Domain Search List, here just for storage size
*/
@@ -203,10 +217,10 @@ 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,
-
{ { OPT_IA_NA, OPT_SIZE_CONV(sizeof(struct opt_ia_na) +
sizeof(struct opt_ia_addr) -
sizeof(struct opt_hdr)) },
@@ -228,6 +242,10 @@ static struct resp_t {
{ { OPT_DNS_SEARCH, 0, },
{ 0 },
},
+
+ { { OPT_CLIENT_FQDN, 0, },
+ (uint8_t)~0U, { 0 },
+ },
};
static const struct opt_status_code sc_not_on_link = {
@@ -416,6 +434,29 @@ search:
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)
+{
+ uint16_t hostname_len = strlen(c->hostname.n);
+ if (hostname_len > 0) {
+ struct opt_client_fqdn *o = (struct opt_client_fqdn*)(buf + offset);
+ o->hdr.t = OPT_CLIENT_FQDN;
+ o->hdr.l = htons(hostname_len+2);
+ o->flags = 0x00;
+ *o->hostname = hostname_len;
+ memcpy(o->hostname+1, c->hostname.n, hostname_len);
+ offset += sizeof(struct opt_hdr) + hostname_len+2;
+ }
+ return offset;
+}
+
/**
* dhcpv6() - Check if this is a DHCPv6 message, reply as needed
* @c: Execution context
@@ -549,6 +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.h b/passt.h
index 72c7f72..d9864e6 100644
--- a/passt.h
+++ b/passt.h
@@ -205,6 +205,7 @@ struct ip6_ctx {
* @ifi4: Index of template interface for IPv4, 0 if IPv4 disabled
* @ip: IPv4 configuration
* @dns_search: DNS search list
+ * @hostname: Client hostname
* @ifi6: Index of template interface for IPv6, 0 if IPv6 disabled
* @ip6: IPv6 configuration
* @pasta_ifn: Name of namespace interface for pasta
@@ -262,6 +263,7 @@ struct ctx {
struct ip4_ctx ip4;
struct fqdn dns_search[MAXDNSRCH];
+ struct fqdn hostname;
unsigned int ifi6;
struct ip6_ctx ip6;
diff --git a/test/lib/setup b/test/lib/setup
index 5338393..9c7aac9 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 passt1 -P ${STATESETUP}/passt.pid"
# pidfile isn't created until passt is listening
wait_for [ -f "${STATESETUP}/passt.pid" ]
@@ -146,11 +146,11 @@ 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 passt1 -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 passt1 -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" ]
@@ -215,7 +215,7 @@ setup_two_guests() {
[ ${DEBUG} -eq 1 ] && __opts="${__opts} -d"
[ ${TRACE} -eq 1 ] && __opts="${__opts} --trace"
- 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 ${__opts} -H passt1 -t 10001 -u 10001"
wait_for [ -f "${STATESETUP}/passt_1.pid" ]
__opts=
@@ -223,7 +223,7 @@ setup_two_guests() {
[ ${DEBUG} -eq 1 ] && __opts="${__opts} -d"
[ ${TRACE} -eq 1 ] && __opts="${__opts} --trace"
- 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 ${__opts} --hostname passt2 -t 10004 -u 10004"
wait_for [ -f "${STATESETUP}/passt_2.pid" ]
GUEST_1_CID=94557
diff --git a/test/passt.mbuto b/test/passt.mbuto
index 138d365..bcd9041 100755
--- a/test/passt.mbuto
+++ b/test/passt.mbuto
@@ -55,6 +55,7 @@ set >> \$LOG
[ -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_fqdn_hostname}" ] && hostname "\${new_fqdn_hostname}"
exit 0
EOF
chmod 755 /sbin/dhclient-script
diff --git a/test/passt/dhcp b/test/passt/dhcp
index 9925ab9..36535f2 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 +47,12 @@ 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 HOSTNAME hostname
+check [ "__HOSTNAME__" = "passt1" ]
+
test DHCPv6: address
+guest hostname none
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 +75,7 @@ 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 HOSTNAME hostname
+check [ "__HOSTNAME__" = "passt1" ]
--
@@ -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 +47,12 @@ 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 HOSTNAME hostname
+check [ "__HOSTNAME__" = "passt1" ]
+
test DHCPv6: address
+guest hostname none
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 +75,7 @@ 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 HOSTNAME hostname
+check [ "__HOSTNAME__" = "passt1" ]
--
2.47.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] dhcp, dhcpv6: Add hostname and client fqdn ops
2024-11-14 8:47 [PATCH v2] dhcp, dhcpv6: Add hostname and client fqdn ops Enrique Llorente
@ 2024-11-14 17:13 ` Stefano Brivio
2024-11-15 9:25 ` Enrique Llorente Pastora
0 siblings, 1 reply; 4+ messages in thread
From: Stefano Brivio @ 2024-11-14 17:13 UTC (permalink / raw)
To: Enrique Llorente; +Cc: passt-dev
On Thu, 14 Nov 2024 09:47:27 +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 -H --hostname to configure the DHCPv4 and DHCPv6
> options to will send hostname to clients.
>
> Signed-off-by: Enrique Llorente <ellorent@redhat.com>
> ---
> conf.c | 13 ++++++++++---
> dhcp.c | 8 +++++++-
> dhcpv6.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
> passt.h | 2 ++
> test/lib/setup | 10 +++++-----
> test/passt.mbuto | 1 +
> test/passt/dhcp | 11 ++++++++++-
> 7 files changed, 78 insertions(+), 11 deletions(-)
>
> diff --git a/conf.c b/conf.c
> index 14411b4..ddb585c 100644
> --- a/conf.c
> +++ b/conf.c
> @@ -847,7 +847,8 @@ static void usage(const char *name, FILE *f, int status)
> " --freebind Bind to any address for forwarding\n"
> " --no-map-gw Don't map gateway address to host\n"
> " -4, --ipv4-only Enable IPv4 operation only\n"
> - " -6, --ipv6-only Enable IPv6 operation only\n");
> + " -6, --ipv6-only Enable IPv6 operation only\n"
> + " -H, --hostname NAME Hostname to configure client with\n");
Use one tab instead of one space between "NAME" and "Hostname" so that
the output (and the code itself) is aligned.
>
> if (strstr(name, "pasta"))
> goto pasta_opts;
> @@ -1303,6 +1304,7 @@ void conf(struct ctx *c, int argc, char **argv)
> {"map-guest-addr", required_argument, NULL, 22 },
> {"host-lo-to-ns-lo", no_argument, NULL, 23 },
> {"dns-host", required_argument, NULL, 24 },
> + {"hostname", required_argument, NULL, 'H' },
Maybe this could go a bit more up, just after the "dns" and "search"
options. Two reasons: we have all the options without a short version
at the end, and this logically belongs together with other name-related
stuff we send to the guest.
> { 0 },
> };
> const char *logname = (c->mode == MODE_PASTA) ? "pasta" : "passt";
> @@ -1325,9 +1327,9 @@ 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:46t:u:T:U:H:";
Same here: maybe after S: it makes more sense.
> } 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:461t:u:H:";
> }
>
> c->tcp.fwd_in.mode = c->tcp.fwd_out.mode = FWD_UNSET;
> @@ -1680,6 +1682,11 @@ void conf(struct ctx *c, int argc, char **argv)
>
> c->one_off = true;
> break;
> + case 'H':
> + ret = snprintf(c->hostname.n, sizeof(c->hostname.n), "%s", optarg);
We (generally) wrap lines at 80 columns where doable:
ret = snprintf(c->hostname.n, sizeof(c->hostname.n),
"%s", optarg);
> + if (ret <= 0 || ret >= (int)sizeof(c->hostname.n))
> + die("Invalid hostname: %s", optarg);
> + break;
> case 't':
> case 'u':
> case 'T':
> diff --git a/dhcp.c b/dhcp.c
> index a06f143..ec7e78a 100644
> --- a/dhcp.c
> +++ b/dhcp.c
> @@ -275,7 +275,7 @@ 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;
> char macstr[ETH_ADDRSTRLEN];
> const struct ethhdr *eh;
> const struct iphdr *iph;
> @@ -375,6 +375,12 @@ int dhcp(const struct ctx *c, const struct pool *p)
> opts[6].slen += sizeof(uint32_t);
> }
>
> + hostname_len = strlen(c->hostname.n);
> + if ( hostname_len > 0 ) {
No space around parentheses in expressions:
if (hostname_len > 0) {
> + opts[12].slen = hostname_len;
> + memcpy(opts[12].s, &c->hostname.n, hostname_len);
> + }
> +
> if (!c->no_dhcp_dns_search)
> opt_set_dns_search(c, sizeof(m->o));
>
> diff --git a/dhcpv6.c b/dhcpv6.c
> index 14a5c7e..190dc0e 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)
One tab instead of spaces.
> #define STR_NOTONLINK "Prefix not appropriate for link."
>
> uint16_t l;
> @@ -163,6 +164,18 @@ 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 as stated at RFC 4704
s/stated at/described by/
Maybe mention that we don't really use those ("always zero for us").
> + * @hostname: Client fqdn
A hostname is not necessarily a fully-qualified domain name. The RFC
calls this "domain name", so we could at least call this 'domain' in
the struct to make it clear we're referring to that.
As to what it should contain: RFC 4702 defines option 81 (FQDN) for
DHCP, which is equivalent to DHCPv6's option 39 (RFC 4704). Should we
just call this whole thing "FQDN" and switch to option 81 for DHCP
instead? Would this work for KubeVirt?
Or introduce two options: -H / --hostname (option 12, DHCP only), and
--fqdn (setting both DHCP option 81 and DHCPv6 option 39)?
> + */
> +struct opt_client_fqdn{
> + struct opt_hdr hdr;
> + uint8_t flags;
> + uint8_t hostname[NS_MAXDNAME];
NS_MAXDNAME is typically 1025, I don't remember why it's defined
that way, but we shouldn't accept domain names that are longer than 255
bytes (or maybe even 253 bytes, RFC 1035), because otherwise they will
be different when sent over DHCP (where we have a 255 bytes limit).
Right now we only send domain names as part of the DNS search option,
and there we also use NS_MAXDNAME as limit, but for DHCP, we apply
message compression (RFC 1035 4.1.4). In that case, we might be able to
send domain names that are longer than 255 bytes (because of the
compression).
For simplicity, perhaps we should just stick to 253 bytes for any kind
of domain name. <arpa/nameser.h> doesn't really help us:
#define NS_MAXDNAME 1025 /*%< maximum domain name */
#define NS_MAXCDNAME 255 /*%< maximum compressed domain name */
...so maybe we could define our own MAXDNAME as 253 and be done with it.
> +} __attribute__((packed));
> +
> /**
> * struct msg_hdr - DHCPv6 client/server message header
> * @type: DHCP message type
> @@ -191,6 +204,7 @@ struct msg_hdr {
> * @ia_na: Non-temporary Address option
> * @ia_addr: Address for IA_NA
> * @client_id: Client Identifier, variable length
> + * @client_fqdn: Client FQDN, variable length
> * @dns_servers: DNS Recursive Name Server, here just for storage size
> * @dns_search: Domain Search List, here just for storage size
> */
> @@ -203,10 +217,10 @@ 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;
This should also appear in the description of struct resp_t.
> } __attribute__((__packed__)) resp = {
> { 0 },
> SERVER_ID,
> -
Unrelated change.
> { { OPT_IA_NA, OPT_SIZE_CONV(sizeof(struct opt_ia_na) +
> sizeof(struct opt_ia_addr) -
> sizeof(struct opt_hdr)) },
> @@ -228,6 +242,10 @@ static struct resp_t {
> { { OPT_DNS_SEARCH, 0, },
> { 0 },
> },
> +
> + { { OPT_CLIENT_FQDN, 0, },
> + (uint8_t)~0U, { 0 },
No need to initialise fields here as this member is here just to
calculate the storage size for 'resp_t': 'flags' can be all zeroes.
> + },
> };
>
> static const struct opt_status_code sc_not_on_link = {
> @@ -416,6 +434,29 @@ search:
> 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)
This whole function mixes up spaces and tabs.
> +{
> + uint16_t hostname_len = strlen(c->hostname.n);
> + if (hostname_len > 0) {
> + struct opt_client_fqdn *o = (struct opt_client_fqdn*)(buf + offset);
Space before * (struct opt_client_fqdn *).
> + o->hdr.t = OPT_CLIENT_FQDN;
> + o->hdr.l = htons(hostname_len+2);
Spaces around operands (hostname_len + 2).
> + o->flags = 0x00;
> + *o->hostname = hostname_len;
> + memcpy(o->hostname+1, c->hostname.n, hostname_len);
Same here (o->hostname + 1).
> + offset += sizeof(struct opt_hdr) + hostname_len+2;
And here.
> + }
> + return offset;
> +}
> +
> /**
> * dhcpv6() - Check if this is a DHCPv6 message, reply as needed
> * @c: Execution context
> @@ -549,6 +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.h b/passt.h
> index 72c7f72..d9864e6 100644
> --- a/passt.h
> +++ b/passt.h
> @@ -205,6 +205,7 @@ struct ip6_ctx {
> * @ifi4: Index of template interface for IPv4, 0 if IPv4 disabled
> * @ip: IPv4 configuration
> * @dns_search: DNS search list
> + * @hostname: Client hostname
> * @ifi6: Index of template interface for IPv6, 0 if IPv6 disabled
> * @ip6: IPv6 configuration
> * @pasta_ifn: Name of namespace interface for pasta
> @@ -262,6 +263,7 @@ struct ctx {
> struct ip4_ctx ip4;
>
> struct fqdn dns_search[MAXDNSRCH];
> + struct fqdn hostname;
Same here: FQDN and hostname aren't necessarily the same thing. We
should pick one, or add two separate options. Or even just --fqdn if
it's what KubeVirt needs.
>
> unsigned int ifi6;
> struct ip6_ctx ip6;
> diff --git a/test/lib/setup b/test/lib/setup
> index 5338393..9c7aac9 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 passt1 -P ${STATESETUP}/passt.pid"
>
> # pidfile isn't created until passt is listening
> wait_for [ -f "${STATESETUP}/passt.pid" ]
> @@ -146,11 +146,11 @@ 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 passt1 -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 passt1 -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" ]
>
> @@ -215,7 +215,7 @@ setup_two_guests() {
> [ ${DEBUG} -eq 1 ] && __opts="${__opts} -d"
> [ ${TRACE} -eq 1 ] && __opts="${__opts} --trace"
>
> - 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 ${__opts} -H passt1 -t 10001 -u 10001"
> wait_for [ -f "${STATESETUP}/passt_1.pid" ]
>
> __opts=
> @@ -223,7 +223,7 @@ setup_two_guests() {
> [ ${DEBUG} -eq 1 ] && __opts="${__opts} -d"
> [ ${TRACE} -eq 1 ] && __opts="${__opts} --trace"
>
> - 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 ${__opts} --hostname passt2 -t 10004 -u 10004"
> wait_for [ -f "${STATESETUP}/passt_2.pid" ]
>
> GUEST_1_CID=94557
> diff --git a/test/passt.mbuto b/test/passt.mbuto
> index 138d365..bcd9041 100755
> --- a/test/passt.mbuto
> +++ b/test/passt.mbuto
> @@ -55,6 +55,7 @@ set >> \$LOG
> [ -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_fqdn_hostname}" ] && hostname "\${new_fqdn_hostname}"
> exit 0
> EOF
> chmod 755 /sbin/dhclient-script
> diff --git a/test/passt/dhcp b/test/passt/dhcp
> index 9925ab9..36535f2 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 +47,12 @@ 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 HOSTNAME hostname
> +check [ "__HOSTNAME__" = "passt1" ]
> +
> test DHCPv6: address
> +guest hostname none
> 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 +75,7 @@ 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 HOSTNAME hostname
> +check [ "__HOSTNAME__" = "passt1" ]
The rest looks good to me.
--
Stefano
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] dhcp, dhcpv6: Add hostname and client fqdn ops
2024-11-14 17:13 ` Stefano Brivio
@ 2024-11-15 9:25 ` Enrique Llorente Pastora
2024-11-15 11:28 ` Stefano Brivio
0 siblings, 1 reply; 4+ messages in thread
From: Enrique Llorente Pastora @ 2024-11-15 9:25 UTC (permalink / raw)
To: Stefano Brivio; +Cc: passt-dev
On Thu, Nov 14, 2024 at 6:13 PM Stefano Brivio <sbrivio@redhat.com> wrote:
>
> On Thu, 14 Nov 2024 09:47:27 +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 -H --hostname to configure the DHCPv4 and DHCPv6
> > options to will send hostname to clients.
> >
> > Signed-off-by: Enrique Llorente <ellorent@redhat.com>
> > ---
> > conf.c | 13 ++++++++++---
> > dhcp.c | 8 +++++++-
> > dhcpv6.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
> > passt.h | 2 ++
> > test/lib/setup | 10 +++++-----
> > test/passt.mbuto | 1 +
> > test/passt/dhcp | 11 ++++++++++-
> > 7 files changed, 78 insertions(+), 11 deletions(-)
> >
> > diff --git a/conf.c b/conf.c
> > index 14411b4..ddb585c 100644
> > --- a/conf.c
> > +++ b/conf.c
> > @@ -847,7 +847,8 @@ static void usage(const char *name, FILE *f, int status)
> > " --freebind Bind to any address for forwarding\n"
> > " --no-map-gw Don't map gateway address to host\n"
> > " -4, --ipv4-only Enable IPv4 operation only\n"
> > - " -6, --ipv6-only Enable IPv6 operation only\n");
> > + " -6, --ipv6-only Enable IPv6 operation only\n"
> > + " -H, --hostname NAME Hostname to configure client with\n");
>
> Use one tab instead of one space between "NAME" and "Hostname" so that
> the output (and the code itself) is aligned.
>
> >
> > if (strstr(name, "pasta"))
> > goto pasta_opts;
> > @@ -1303,6 +1304,7 @@ void conf(struct ctx *c, int argc, char **argv)
> > {"map-guest-addr", required_argument, NULL, 22 },
> > {"host-lo-to-ns-lo", no_argument, NULL, 23 },
> > {"dns-host", required_argument, NULL, 24 },
> > + {"hostname", required_argument, NULL, 'H' },
>
> Maybe this could go a bit more up, just after the "dns" and "search"
> options. Two reasons: we have all the options without a short version
> at the end, and this logically belongs together with other name-related
> stuff we send to the guest.
>
> > { 0 },
> > };
> > const char *logname = (c->mode == MODE_PASTA) ? "pasta" : "passt";
> > @@ -1325,9 +1327,9 @@ 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:46t:u:T:U:H:";
>
> Same here: maybe after S: it makes more sense.
>
> > } 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:461t:u:H:";
> > }
> >
> > c->tcp.fwd_in.mode = c->tcp.fwd_out.mode = FWD_UNSET;
> > @@ -1680,6 +1682,11 @@ void conf(struct ctx *c, int argc, char **argv)
> >
> > c->one_off = true;
> > break;
> > + case 'H':
> > + ret = snprintf(c->hostname.n, sizeof(c->hostname.n), "%s", optarg);
>
> We (generally) wrap lines at 80 columns where doable:
>
> ret = snprintf(c->hostname.n, sizeof(c->hostname.n),
> "%s", optarg);
>
> > + if (ret <= 0 || ret >= (int)sizeof(c->hostname.n))
> > + die("Invalid hostname: %s", optarg);
> > + break;
> > case 't':
> > case 'u':
> > case 'T':
> > diff --git a/dhcp.c b/dhcp.c
> > index a06f143..ec7e78a 100644
> > --- a/dhcp.c
> > +++ b/dhcp.c
> > @@ -275,7 +275,7 @@ 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;
> > char macstr[ETH_ADDRSTRLEN];
> > const struct ethhdr *eh;
> > const struct iphdr *iph;
> > @@ -375,6 +375,12 @@ int dhcp(const struct ctx *c, const struct pool *p)
> > opts[6].slen += sizeof(uint32_t);
> > }
> >
> > + hostname_len = strlen(c->hostname.n);
> > + if ( hostname_len > 0 ) {
>
> No space around parentheses in expressions:
>
> if (hostname_len > 0) {
>
> > + opts[12].slen = hostname_len;
> > + memcpy(opts[12].s, &c->hostname.n, hostname_len);
> > + }
> > +
> > if (!c->no_dhcp_dns_search)
> > opt_set_dns_search(c, sizeof(m->o));
> >
> > diff --git a/dhcpv6.c b/dhcpv6.c
> > index 14a5c7e..190dc0e 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)
>
> One tab instead of spaces.
>
> > #define STR_NOTONLINK "Prefix not appropriate for link."
> >
> > uint16_t l;
> > @@ -163,6 +164,18 @@ 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 as stated at RFC 4704
>
> s/stated at/described by/
>
> Maybe mention that we don't really use those ("always zero for us").
>
> > + * @hostname: Client fqdn
>
> A hostname is not necessarily a fully-qualified domain name. The RFC
> calls this "domain name", so we could at least call this 'domain' in
> the struct to make it clear we're referring to that.
>
> As to what it should contain: RFC 4702 defines option 81 (FQDN) for
> DHCP, which is equivalent to DHCPv6's option 39 (RFC 4704). Should we
> just call this whole thing "FQDN" and switch to option 81 for DHCP
> instead? Would this work for KubeVirt?
>
> Or introduce two options: -H / --hostname (option 12, DHCP only), and
> --fqdn (setting both DHCP option 81 and DHCPv6 option 39)?
Let me experiment with DHCPv4 option 81 with kubevirt machines, if it's enough
we use 81 instead of 12 and call it --fqdn.
If not we go with --fqdn and --hostname, but in this case it's not
clear to me what kubevirt/libvirt
has to pass though, also is this going to be expose at the domain xml
or libvirt will directly pass always
the vm name as one of them ? (for dual stack or single stack ipv4
hostname is enough, problem is single stack ipv6)
>
> > + */
> > +struct opt_client_fqdn{
> > + struct opt_hdr hdr;
> > + uint8_t flags;
> > + uint8_t hostname[NS_MAXDNAME];
>
> NS_MAXDNAME is typically 1025, I don't remember why it's defined
> that way, but we shouldn't accept domain names that are longer than 255
> bytes (or maybe even 253 bytes, RFC 1035), because otherwise they will
> be different when sent over DHCP (where we have a 255 bytes limit).
>
> Right now we only send domain names as part of the DNS search option,
> and there we also use NS_MAXDNAME as limit, but for DHCP, we apply
> message compression (RFC 1035 4.1.4). In that case, we might be able to
> send domain names that are longer than 255 bytes (because of the
> compression).
>
> For simplicity, perhaps we should just stick to 253 bytes for any kind
> of domain name. <arpa/nameser.h> doesn't really help us:
>
> #define NS_MAXDNAME 1025 /*%< maximum domain name */
>
> #define NS_MAXCDNAME 255 /*%< maximum compressed domain name */
>
> ...so maybe we could define our own MAXDNAME as 253 and be done with it.
Make sense, did use the limit found around.
>
> > +} __attribute__((packed));
> > +
> > /**
> > * struct msg_hdr - DHCPv6 client/server message header
> > * @type: DHCP message type
> > @@ -191,6 +204,7 @@ struct msg_hdr {
> > * @ia_na: Non-temporary Address option
> > * @ia_addr: Address for IA_NA
> > * @client_id: Client Identifier, variable length
> > + * @client_fqdn: Client FQDN, variable length
> > * @dns_servers: DNS Recursive Name Server, here just for storage size
> > * @dns_search: Domain Search List, here just for storage size
> > */
> > @@ -203,10 +217,10 @@ 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;
>
> This should also appear in the description of struct resp_t.
>
> > } __attribute__((__packed__)) resp = {
> > { 0 },
> > SERVER_ID,
> > -
>
> Unrelated change.
>
> > { { OPT_IA_NA, OPT_SIZE_CONV(sizeof(struct opt_ia_na) +
> > sizeof(struct opt_ia_addr) -
> > sizeof(struct opt_hdr)) },
> > @@ -228,6 +242,10 @@ static struct resp_t {
> > { { OPT_DNS_SEARCH, 0, },
> > { 0 },
> > },
> > +
> > + { { OPT_CLIENT_FQDN, 0, },
> > + (uint8_t)~0U, { 0 },
>
> No need to initialise fields here as this member is here just to
> calculate the storage size for 'resp_t': 'flags' can be all zeroes.
>
> > + },
> > };
> >
> > static const struct opt_status_code sc_not_on_link = {
> > @@ -416,6 +434,29 @@ search:
> > 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)
>
> This whole function mixes up spaces and tabs.
>
> > +{
> > + uint16_t hostname_len = strlen(c->hostname.n);
> > + if (hostname_len > 0) {
> > + struct opt_client_fqdn *o = (struct opt_client_fqdn*)(buf + offset);
>
> Space before * (struct opt_client_fqdn *).
>
> > + o->hdr.t = OPT_CLIENT_FQDN;
> > + o->hdr.l = htons(hostname_len+2);
>
> Spaces around operands (hostname_len + 2).
>
> > + o->flags = 0x00;
> > + *o->hostname = hostname_len;
> > + memcpy(o->hostname+1, c->hostname.n, hostname_len);
>
> Same here (o->hostname + 1).
>
> > + offset += sizeof(struct opt_hdr) + hostname_len+2;
>
> And here.
>
> > + }
> > + return offset;
> > +}
> > +
> > /**
> > * dhcpv6() - Check if this is a DHCPv6 message, reply as needed
> > * @c: Execution context
> > @@ -549,6 +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.h b/passt.h
> > index 72c7f72..d9864e6 100644
> > --- a/passt.h
> > +++ b/passt.h
> > @@ -205,6 +205,7 @@ struct ip6_ctx {
> > * @ifi4: Index of template interface for IPv4, 0 if IPv4 disabled
> > * @ip: IPv4 configuration
> > * @dns_search: DNS search list
> > + * @hostname: Client hostname
> > * @ifi6: Index of template interface for IPv6, 0 if IPv6 disabled
> > * @ip6: IPv6 configuration
> > * @pasta_ifn: Name of namespace interface for pasta
> > @@ -262,6 +263,7 @@ struct ctx {
> > struct ip4_ctx ip4;
> >
> > struct fqdn dns_search[MAXDNSRCH];
> > + struct fqdn hostname;
>
> Same here: FQDN and hostname aren't necessarily the same thing. We
> should pick one, or add two separate options. Or even just --fqdn if
> it's what KubeVirt needs.
>
> >
> > unsigned int ifi6;
> > struct ip6_ctx ip6;
> > diff --git a/test/lib/setup b/test/lib/setup
> > index 5338393..9c7aac9 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 passt1 -P ${STATESETUP}/passt.pid"
> >
> > # pidfile isn't created until passt is listening
> > wait_for [ -f "${STATESETUP}/passt.pid" ]
> > @@ -146,11 +146,11 @@ 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 passt1 -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 passt1 -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" ]
> >
> > @@ -215,7 +215,7 @@ setup_two_guests() {
> > [ ${DEBUG} -eq 1 ] && __opts="${__opts} -d"
> > [ ${TRACE} -eq 1 ] && __opts="${__opts} --trace"
> >
> > - 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 ${__opts} -H passt1 -t 10001 -u 10001"
> > wait_for [ -f "${STATESETUP}/passt_1.pid" ]
> >
> > __opts=
> > @@ -223,7 +223,7 @@ setup_two_guests() {
> > [ ${DEBUG} -eq 1 ] && __opts="${__opts} -d"
> > [ ${TRACE} -eq 1 ] && __opts="${__opts} --trace"
> >
> > - 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 ${__opts} --hostname passt2 -t 10004 -u 10004"
> > wait_for [ -f "${STATESETUP}/passt_2.pid" ]
> >
> > GUEST_1_CID=94557
> > diff --git a/test/passt.mbuto b/test/passt.mbuto
> > index 138d365..bcd9041 100755
> > --- a/test/passt.mbuto
> > +++ b/test/passt.mbuto
> > @@ -55,6 +55,7 @@ set >> \$LOG
> > [ -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_fqdn_hostname}" ] && hostname "\${new_fqdn_hostname}"
> > exit 0
> > EOF
> > chmod 755 /sbin/dhclient-script
> > diff --git a/test/passt/dhcp b/test/passt/dhcp
> > index 9925ab9..36535f2 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 +47,12 @@ 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 HOSTNAME hostname
> > +check [ "__HOSTNAME__" = "passt1" ]
> > +
> > test DHCPv6: address
> > +guest hostname none
> > 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 +75,7 @@ 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 HOSTNAME hostname
> > +check [ "__HOSTNAME__" = "passt1" ]
>
> The rest looks good to me.
>
> --
> Stefano
>
--
Quique Llorente
CNV networking Senior Software Engineer
Red Hat EMEA
ellorent@redhat.com
@RedHat Red Hat Red Hat
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] dhcp, dhcpv6: Add hostname and client fqdn ops
2024-11-15 9:25 ` Enrique Llorente Pastora
@ 2024-11-15 11:28 ` Stefano Brivio
0 siblings, 0 replies; 4+ messages in thread
From: Stefano Brivio @ 2024-11-15 11:28 UTC (permalink / raw)
To: Enrique Llorente Pastora; +Cc: passt-dev
On Fri, 15 Nov 2024 10:25:33 +0100
Enrique Llorente Pastora <ellorent@redhat.com> wrote:
> On Thu, Nov 14, 2024 at 6:13 PM Stefano Brivio <sbrivio@redhat.com> wrote:
> >
> > On Thu, 14 Nov 2024 09:47:27 +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 -H --hostname to configure the DHCPv4 and DHCPv6
> > > options to will send hostname to clients.
> > >
> > > Signed-off-by: Enrique Llorente <ellorent@redhat.com>
> > > ---
> > > conf.c | 13 ++++++++++---
> > > dhcp.c | 8 +++++++-
> > > dhcpv6.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
> > > passt.h | 2 ++
> > > test/lib/setup | 10 +++++-----
> > > test/passt.mbuto | 1 +
> > > test/passt/dhcp | 11 ++++++++++-
> > > 7 files changed, 78 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/conf.c b/conf.c
> > > index 14411b4..ddb585c 100644
> > > --- a/conf.c
> > > +++ b/conf.c
> > > @@ -847,7 +847,8 @@ static void usage(const char *name, FILE *f, int status)
> > > " --freebind Bind to any address for forwarding\n"
> > > " --no-map-gw Don't map gateway address to host\n"
> > > " -4, --ipv4-only Enable IPv4 operation only\n"
> > > - " -6, --ipv6-only Enable IPv6 operation only\n");
> > > + " -6, --ipv6-only Enable IPv6 operation only\n"
> > > + " -H, --hostname NAME Hostname to configure client with\n");
> >
> > Use one tab instead of one space between "NAME" and "Hostname" so that
> > the output (and the code itself) is aligned.
> >
> > >
> > > if (strstr(name, "pasta"))
> > > goto pasta_opts;
> > > @@ -1303,6 +1304,7 @@ void conf(struct ctx *c, int argc, char **argv)
> > > {"map-guest-addr", required_argument, NULL, 22 },
> > > {"host-lo-to-ns-lo", no_argument, NULL, 23 },
> > > {"dns-host", required_argument, NULL, 24 },
> > > + {"hostname", required_argument, NULL, 'H' },
> >
> > Maybe this could go a bit more up, just after the "dns" and "search"
> > options. Two reasons: we have all the options without a short version
> > at the end, and this logically belongs together with other name-related
> > stuff we send to the guest.
> >
> > > { 0 },
> > > };
> > > const char *logname = (c->mode == MODE_PASTA) ? "pasta" : "passt";
> > > @@ -1325,9 +1327,9 @@ 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:46t:u:T:U:H:";
> >
> > Same here: maybe after S: it makes more sense.
> >
> > > } 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:461t:u:H:";
> > > }
> > >
> > > c->tcp.fwd_in.mode = c->tcp.fwd_out.mode = FWD_UNSET;
> > > @@ -1680,6 +1682,11 @@ void conf(struct ctx *c, int argc, char **argv)
> > >
> > > c->one_off = true;
> > > break;
> > > + case 'H':
> > > + ret = snprintf(c->hostname.n, sizeof(c->hostname.n), "%s", optarg);
> >
> > We (generally) wrap lines at 80 columns where doable:
> >
> > ret = snprintf(c->hostname.n, sizeof(c->hostname.n),
> > "%s", optarg);
> >
> > > + if (ret <= 0 || ret >= (int)sizeof(c->hostname.n))
> > > + die("Invalid hostname: %s", optarg);
> > > + break;
> > > case 't':
> > > case 'u':
> > > case 'T':
> > > diff --git a/dhcp.c b/dhcp.c
> > > index a06f143..ec7e78a 100644
> > > --- a/dhcp.c
> > > +++ b/dhcp.c
> > > @@ -275,7 +275,7 @@ 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;
> > > char macstr[ETH_ADDRSTRLEN];
> > > const struct ethhdr *eh;
> > > const struct iphdr *iph;
> > > @@ -375,6 +375,12 @@ int dhcp(const struct ctx *c, const struct pool *p)
> > > opts[6].slen += sizeof(uint32_t);
> > > }
> > >
> > > + hostname_len = strlen(c->hostname.n);
> > > + if ( hostname_len > 0 ) {
> >
> > No space around parentheses in expressions:
> >
> > if (hostname_len > 0) {
> >
> > > + opts[12].slen = hostname_len;
> > > + memcpy(opts[12].s, &c->hostname.n, hostname_len);
> > > + }
> > > +
> > > if (!c->no_dhcp_dns_search)
> > > opt_set_dns_search(c, sizeof(m->o));
> > >
> > > diff --git a/dhcpv6.c b/dhcpv6.c
> > > index 14a5c7e..190dc0e 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)
> >
> > One tab instead of spaces.
> >
> > > #define STR_NOTONLINK "Prefix not appropriate for link."
> > >
> > > uint16_t l;
> > > @@ -163,6 +164,18 @@ 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 as stated at RFC 4704
> >
> > s/stated at/described by/
> >
> > Maybe mention that we don't really use those ("always zero for us").
> >
> > > + * @hostname: Client fqdn
> >
> > A hostname is not necessarily a fully-qualified domain name. The RFC
> > calls this "domain name", so we could at least call this 'domain' in
> > the struct to make it clear we're referring to that.
> >
> > As to what it should contain: RFC 4702 defines option 81 (FQDN) for
> > DHCP, which is equivalent to DHCPv6's option 39 (RFC 4704). Should we
> > just call this whole thing "FQDN" and switch to option 81 for DHCP
> > instead? Would this work for KubeVirt?
> >
> > Or introduce two options: -H / --hostname (option 12, DHCP only), and
> > --fqdn (setting both DHCP option 81 and DHCPv6 option 39)?
>
> Let me experiment with DHCPv4 option 81 with kubevirt machines, if it's enough
> we use 81 instead of 12 and call it --fqdn.
>
> If not we go with --fqdn and --hostname, but in this case it's not
> clear to me what kubevirt/libvirt
> has to pass though, also is this going to be expose at the domain xml
> or libvirt will directly pass always
> the vm name as one of them ? (for dual stack or single stack ipv4
> hostname is enough, problem is single stack ipv6)
Note that they are (of course) different things, and neither RFC 4702
nor RFC 4703 make any mention whatsoever of hostname and option 12.
That is, you could legitimately pass x as hostname and y.tld as FQDN
(which gives 'y' as hostname... but RFCs don't specify which one wins).
I think for libvirt we should propose to add one or two separate
attributes ("hostname" / "fqdn"), and not imply them from the name of
the machine or "domain" (the guest "domain", nothing to do with network
domain), because that's not necessarily what users want.
About option 81 itself: it's not just a matter of changing the number,
unfortunately. You would need to set the 'E' flag. We have an
implementation of name compression according to RFC 1035, 4.1.4 in
opt_set_dns_search(), but RFC 4702 says we shouldn't use it.
No other flags set, as those are for clients.
But there's another aspect, RFC 4702 section 2:
Only one Client FQDN option MAY appear in a message, though it may be
instantiated in a message as multiple options [9]. DHCP clients and
servers supporting this option MUST implement DHCP option
concatenation [9]. In the terminology of [9], the Client FQDN option
is a concatenation-requiring option.
...and we don't support concatenation as described by RFC 3396. The
messy part of it would be option overload (RFC 2131), which we don't do
at all. But RFC 3396 doesn't make it mandatory.
The question is whether we would practically need it though: can we,
with option 81, reasonably end up with UDP packets that are too large,
so we need to resort to option overload?
I mean, it's nothing crazy to add, it's just a bit of pointer trickery.
As a first step, *if* option 81 helps, I would just stick to what's
mandatory (including option concatenation in the "options" section,
that is, n parts of options where options < n have 255 as length).
Maybe, even before that, we could simply accept FQDNs up to 255 (253,
even) bytes.
As a second step we could look into option overload.
--
Stefano
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-11-15 11:29 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-11-14 8:47 [PATCH v2] dhcp, dhcpv6: Add hostname and client fqdn ops Enrique Llorente
2024-11-14 17:13 ` Stefano Brivio
2024-11-15 9:25 ` Enrique Llorente Pastora
2024-11-15 11:28 ` Stefano Brivio
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