On Thu, 14 Nov 2024 09:47:27 +0100 Enrique Llorente <ellorent(a)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(a)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 4704s/stated at/described by/ Maybe mention that we don't really use those ("always zero for us").+ * @hostname: Client fqdnA 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(a)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