On Thu, Jun 25, 2026 at 10:45:07PM -0400, Jon Maloy wrote: > As preparation for supporting multiple addresses per interface, > we replace the single addr/prefix_len fields with an array. The > array consists of a new struct inany_addr_entry containing an > address and prefix length, both in inany_addr format. > > Despite some code refactoring, there are only two real functional > changes: > - The indicated IPv6 prefix length is now properly stored, instead > of being ignored and overridden with the hardcoded value 64, as > has been the case until now. > - Since even IPv4 addresses now are stored in IPv6 format, we > also store the corresponding prefix length in that format, > i.e. using the range [96,128] instead of [0,32]. > > In conf_ip6(), the explicit IN6_IS_ADDR_UNSPECIFIED() check on the > address at the end of the function is no longer needed: for > host-discovered addresses, it is now checked inside the if (!a) block > before calling fwd_set_addr(); for user-provided addresses (via -a), > validation already rejects unspecified addresses at parse time. > > Signed-off-by: Jon Maloy > > --- > v2: -Using inany_addr instead of protocol specific addresses as > entry address field. > > v3: -Merging into one array, directly in struct ctx > -Changed prefix_len and flags fields in struct inany_addr_entry > to uint8_t, since that makes the struct directly migratable > > v4: -Updated according to changes in previous commits > -Updated according to feedback from David G. > -Squashed IP4_MASK macro commit into this one > > v6: -Renamed and moved some definitions > -Introduced fwd_set_addr() and fwd_get_addr() already in this commit > -Eliminated first_v4/v6() functions, replaced with fwd_get_addr() > -Some other changes as suggested by David G. > -I kept the flag CONF_ADDR_LINKLOCAL, since it will be > needed later in an address selection function. > > v7: -Introduced CONF_ADDR_GENERATED flag > -Other fixes based on feedback from David and Stefano. > -I changed signature of inany_prefix_len(), but I did not change > its semantics, since the premise of David's comment is wrong: the > caller does *not* explicitly know he is dealing with an IPv4 address. > In fact, there are examples later in this series where it may be an > IPv6 address, and the caller just trusts he gets the return value in > the appropriate format. > -Intoduced the inverse of inany_prefix_len(), called inany_prefix_len6() > which always returns the prefix in IPv6 or mapped IPv4 format. > The name of the function isn't great, but any alternative I came up > with became too long to be practical. > > v8: -Added inany_prefix_v4() (David G.) to extract IPv4 address and > prefix length simultaneously, replacing inany_prefix_len(). > -Removed both inany_prefix_len() and inany_prefix_len6() > auto-detecting functions. Prefix length attached to an inany is > now always stored in IPv6 format (96-128 for IPv4-mapped). > -fwd_set_addr() now requires prefix_len in IPv6 format; callers > updated to pass prefix_len + 96 for IPv4 addresses. > -Fixed -n option to store prefix_len in IPv6 format. > -Fixed addr_seen regression: when address was set via -a, > addr_seen was not initialised in conf_ip4(). > -Replaced assert() with graceful no-op in dhcp.c and ndp.c when > no address is configured (David G.). > -Note: addr_seen is still initialised both at conf_ip*() time > and at DHCP/DHCPv6 send time (David's concern). This > inconsistency will be addressed in a follow-up. > -Introduced a new CONF_ADDR_ANY macro tobe used for address > selection, as suggested by Stefano. > -Deferred introduction of an explicit scope field (replacing > CONF_ADDR_LINKLOCAL flag) to a later commit or series. > --- > arp.c | 12 ++++- > conf.c | 142 +++++++++++++++++++++++++++++++------------------------ > dhcp.c | 19 ++++++-- > dhcpv6.c | 15 ++++-- > fwd.c | 111 +++++++++++++++++++++++++++++++++++-------- > fwd.h | 4 ++ > inany.h | 28 +++++++++++ > ip.h | 2 + > ndp.c | 19 ++++++-- > passt.h | 66 +++++++++++++++++++++++--- > pasta.c | 26 ++++++---- > tap.c | 8 +++- > 12 files changed, 342 insertions(+), 110 deletions(-) > > diff --git a/arp.c b/arp.c > index bb042e95..0392861d 100644 > --- a/arp.c > +++ b/arp.c > @@ -41,6 +41,8 @@ > static bool ignore_arp(const struct ctx *c, > const struct arphdr *ah, const struct arpmsg *am) > { > + const struct guest_addr *a; > + > if (ah->ar_hrd != htons(ARPHRD_ETHER) || > ah->ar_pro != htons(ETH_P_IP) || > ah->ar_hln != ETH_ALEN || > @@ -54,7 +56,8 @@ static bool ignore_arp(const struct ctx *c, > return true; > > /* Don't resolve the guest's assigned address, either. */ > - if (!memcmp(am->tip, &c->ip4.addr, sizeof(am->tip))) > + a = fwd_get_addr(c, AF_INET, CONF_ADDR_ANY, 0); > + if (a && !memcmp(am->tip, inany_v4(&a->addr), sizeof(am->tip))) > return true; > > return false; > @@ -123,12 +126,17 @@ int arp(const struct ctx *c, struct iov_tail *data) > */ > void arp_send_init_req(const struct ctx *c) > { > + const struct guest_addr *a; > struct { > struct ethhdr eh; > struct arphdr ah; > struct arpmsg am; > } __attribute__((__packed__)) req; > > + a = fwd_get_addr(c, AF_INET, CONF_ADDR_ANY, 0); > + if (!a) > + return; > + > /* Ethernet header */ > req.eh.h_proto = htons(ETH_P_ARP); > memcpy(req.eh.h_dest, MAC_BROADCAST, sizeof(req.eh.h_dest)); > @@ -145,7 +153,7 @@ void arp_send_init_req(const struct ctx *c) > memcpy(req.am.sha, c->our_tap_mac, sizeof(req.am.sha)); > memcpy(req.am.sip, &c->ip4.our_tap_addr, sizeof(req.am.sip)); > memcpy(req.am.tha, MAC_BROADCAST, sizeof(req.am.tha)); > - memcpy(req.am.tip, &c->ip4.addr, sizeof(req.am.tip)); > + memcpy(req.am.tip, inany_v4(&a->addr), sizeof(req.am.tip)); > > debug("Sending initial ARP request for guest MAC address"); > tap_send_single(c, &req, sizeof(req)); > diff --git a/conf.c b/conf.c > index 4755a9f4..ac8facc8 100644 > --- a/conf.c > +++ b/conf.c > @@ -373,13 +373,16 @@ static int conf_ip4_prefix(const char *arg) > > /** > * conf_ip4() - Verify or detect IPv4 support, get relevant addresses > + * @c: Execution context > * @ifi: Host interface to attempt (0 to determine one) > - * @ip4: IPv4 context (will be written) > * > * Return: interface index for IPv4, or 0 on failure. > */ > -static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4) > +static unsigned int conf_ip4(struct ctx *c, unsigned int ifi) > { > + const struct guest_addr *a = fwd_get_addr(c, AF_INET, CONF_ADDR_ANY, 0); > + struct ip4_ctx *ip4 = &c->ip4; > + > if (!ifi) > ifi = nl_get_ext_if(nl_sock, AF_INET); > > @@ -398,60 +401,58 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4) > } > } > > - if (IN4_IS_ADDR_UNSPECIFIED(&ip4->addr)) { > + if (!a) { > + struct in_addr addr; > + int prefix_len; > int rc = nl_addr_get(nl_sock, ifi, AF_INET, > - &ip4->addr, &ip4->prefix_len, NULL); > + &addr, &prefix_len, NULL); > if (rc < 0) { > debug("Couldn't discover IPv4 address: %s", > strerror_(-rc)); > return 0; > } > - } > + if (IN4_IS_ADDR_UNSPECIFIED(&addr)) > + return 0; Nit: If we get here, the netlink probe succeeded, and the host apparently has an address of 0.0.0.0. That's pretty strange, and probably warrants a warn(). > > - if (!ip4->prefix_len) { > - in_addr_t addr = ntohl(ip4->addr.s_addr); > - if (IN_CLASSA(addr)) > - ip4->prefix_len = (32 - IN_CLASSA_NSHIFT); > - else if (IN_CLASSB(addr)) > - ip4->prefix_len = (32 - IN_CLASSB_NSHIFT); > - else if (IN_CLASSC(addr)) > - ip4->prefix_len = (32 - IN_CLASSC_NSHIFT); > - else > - ip4->prefix_len = 32; > + fwd_set_addr(c, &inany_from_v4(addr), CONF_ADDR_HOST, > + prefix_len + 96); > } > > - ip4->addr_seen = ip4->addr; > - > + a = fwd_get_addr(c, AF_INET, CONF_ADDR_ANY, 0); Nit: maybe assert(a), since I doubt static checkers will be able to reason that the fwd_set_addr() above means this fwd_get_addr() can't fail. Also, I think that go inside the if block, since the other case means we already have a perfectly good a. > + ip4->addr_seen = *inany_v4(&a->addr); > ip4->our_tap_addr = ip4->guest_gw; > > - if (IN4_IS_ADDR_UNSPECIFIED(&ip4->addr)) > - return 0; > - > return ifi; > } > > /** > * conf_ip4_local() - Configure IPv4 addresses and attributes for local mode > - * @ip4: IPv4 context (will be written) > + * @c: Execution context (will be written) > */ > -static void conf_ip4_local(struct ip4_ctx *ip4) > +static void conf_ip4_local(struct ctx *c) > { > - ip4->addr_seen = ip4->addr = IP4_LL_GUEST_ADDR; > - ip4->our_tap_addr = ip4->guest_gw = IP4_LL_GUEST_GW; > - ip4->prefix_len = IP4_LL_PREFIX_LEN; > + struct ip4_ctx *ip4 = &c->ip4; > > + ip4->addr_seen = IP4_LL_GUEST_ADDR; > + ip4->our_tap_addr = ip4->guest_gw = IP4_LL_GUEST_GW; > ip4->no_copy_addrs = ip4->no_copy_routes = true; > + fwd_set_addr(c, &inany_from_v4(IP4_LL_GUEST_ADDR), > + CONF_ADDR_GENERATED | CONF_ADDR_LINKLOCAL, > + IP4_LL_PREFIX_LEN + 96); > } > > /** > * conf_ip6() - Verify or detect IPv6 support, get relevant addresses > + * @c: Execution context > * @ifi: Host interface to attempt (0 to determine one) > - * @ip6: IPv6 context (will be written) > * > * Return: interface index for IPv6, or 0 on failure. > */ > -static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6) > +static unsigned int conf_ip6(struct ctx *c, unsigned int ifi) > { > + struct ip6_ctx *ip6 = &c->ip6; > + const struct guest_addr *a; > + union inany_addr addr; > int prefix_len = 0; > int rc; > > @@ -472,21 +473,28 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6) > } > } > > - rc = nl_addr_get(nl_sock, ifi, AF_INET6, > - IN6_IS_ADDR_UNSPECIFIED(&ip6->addr) ? &ip6->addr : NULL, > + rc = nl_addr_get(nl_sock, ifi, AF_INET6, &addr.a6, > &prefix_len, &ip6->our_tap_ll); > if (rc < 0) { > debug("Couldn't discover IPv6 address: %s", strerror_(-rc)); > return 0; > } > > - ip6->addr_seen = ip6->addr; > + a = fwd_get_addr(c, AF_INET6, CONF_ADDR_ANY, 0); > + if (!a) { > + if (IN6_IS_ADDR_UNSPECIFIED(&addr)) > + return 0; > + > + fwd_set_addr(c, &addr, CONF_ADDR_HOST, prefix_len); > + ip6->addr_seen = addr.a6; > + } else { > + ip6->addr_seen = a->addr.a6; > + } > > if (IN6_IS_ADDR_LINKLOCAL(&ip6->guest_gw)) > ip6->our_tap_ll = ip6->guest_gw; > > - if (IN6_IS_ADDR_UNSPECIFIED(&ip6->addr) || > - IN6_IS_ADDR_UNSPECIFIED(&ip6->our_tap_ll)) > + if (IN6_IS_ADDR_UNSPECIFIED(&ip6->our_tap_ll)) > return 0; > > return ifi; > @@ -494,13 +502,13 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6) > > /** > * conf_ip6_local() - Configure IPv6 addresses and attributes for local mode > - * @ip6: IPv6 context (will be written) > + * @c: Execution context (will be written) > */ > -static void conf_ip6_local(struct ip6_ctx *ip6) > +static void conf_ip6_local(struct ctx *c) > { > - ip6->our_tap_ll = ip6->guest_gw = IP6_LL_GUEST_GW; > + c->ip6.our_tap_ll = c->ip6.guest_gw = IP6_LL_GUEST_GW; > > - ip6->no_copy_addrs = ip6->no_copy_routes = true; > + c->ip6.no_copy_addrs = c->ip6.no_copy_routes = true; > } > > /** > @@ -784,6 +792,7 @@ enum passt_modes conf_mode(int argc, char *argv[]) > static void conf_print(const struct ctx *c) > { > char buf[INANY_ADDRSTRLEN]; > + const struct guest_addr *a; > int i; > > if (c->fd_control_listen >= 0) > @@ -831,16 +840,19 @@ static void conf_print(const struct ctx *c) > inet_ntop(AF_INET, &c->ip4.map_host_loopback, > buf, sizeof(buf))); > > - if (!c->no_dhcp) { > + a = fwd_get_addr(c, AF_INET, CONF_ADDR_ANY, 0); > + if (a && !c->no_dhcp) { > uint32_t mask; > + int plen = 0; > > - mask = htonl(0xffffffff << (32 - c->ip4.prefix_len)); > + inany_prefix_v4(&a->addr, a->prefix_len, &plen); > + mask = IN4_MASK(plen); > > info("DHCP:"); > info(" assign: %s", > - inet_ntop(AF_INET, &c->ip4.addr, buf, sizeof(buf))); > + inany_ntop(&a->addr, buf, sizeof(buf))); > info(" mask: %s", > - inet_ntop(AF_INET, &mask, buf, sizeof(buf))); > + inet_ntop(AF_INET, &mask, buf, sizeof(buf))); > info(" router: %s", > inet_ntop(AF_INET, &c->ip4.guest_gw, > buf, sizeof(buf))); > @@ -851,8 +863,8 @@ static void conf_print(const struct ctx *c) > break; > if (!i) > info("DNS:"); > - inet_ntop(AF_INET, &c->ip4.dns[i], buf, sizeof(buf)); > - info(" %s", buf); > + info(" %s", inet_ntop(AF_INET, &c->ip4.dns[i], > + buf, sizeof(buf))); > } > > for (i = 0; *c->dns_search[i].n; i++) { > @@ -877,13 +889,15 @@ static void conf_print(const struct ctx *c) > else > goto dns6; > > - info(" assign: %s", > - inet_ntop(AF_INET6, &c->ip6.addr, buf, sizeof(buf))); > + a = fwd_get_addr(c, AF_INET6, CONF_ADDR_ANY, > + CONF_ADDR_LINKLOCAL); > + if (a) > + info(" assign: %s", > + inany_ntop(&a->addr, buf, sizeof(buf))); > info(" router: %s", > inet_ntop(AF_INET6, &c->ip6.guest_gw, buf, sizeof(buf))); > info(" our link-local: %s", > - inet_ntop(AF_INET6, &c->ip6.our_tap_ll, > - buf, sizeof(buf))); > + inet_ntop(AF_INET6, &c->ip6.our_tap_ll, buf, sizeof(buf))); > > dns6: > for (i = 0; i < ARRAY_SIZE(c->ip6.dns); i++) { > @@ -891,8 +905,10 @@ dns6: > break; > if (!i) > info("DNS:"); > - inet_ntop(AF_INET6, &c->ip6.dns[i], buf, sizeof(buf)); > - info(" %s", buf); > + info(" %s", > + inet_ntop(AF_INET6, &c->ip6.dns[i], > + buf, sizeof(buf))); > + > } > > for (i = 0; *c->dns_search[i].n; i++) { > @@ -1580,21 +1596,19 @@ void conf(struct ctx *c, int argc, char **argv) > IN6_IS_ADDR_V4COMPAT(&addr.a6)) > die("Invalid address: %s", optarg); > > + /* Legacy behaviour: replace existing address if any */ > + fwd_set_addr(c, &addr, CONF_ADDR_USER, prefix_len); > if (inany_v4(&addr)) { > - c->ip4.addr = *inany_v4(&addr); > - c->ip4.prefix_len = prefix_len - 96; > + c->ip4.no_copy_addrs = true; > c->ip4.addr_fixed = true; > - if (c->mode == MODE_PASTA) > - c->ip4.no_copy_addrs = true; > } else { > - c->ip6.addr = addr.a6; > + c->ip6.no_copy_addrs = true; > c->ip6.addr_fixed = true; > - if (c->mode == MODE_PASTA) > - c->ip6.no_copy_addrs = true; > } > break; > } > case 'n': { > + struct guest_addr *a; > int plen; > > if (addr_has_prefix_len) > @@ -1604,8 +1618,12 @@ void conf(struct ctx *c, int argc, char **argv) > if (plen < 0) > die("Invalid prefix length: %s", optarg); > > - prefix_len_from_opt = plen + 96; > - c->ip4.prefix_len = plen; > + prefix_len_from_opt = plen; Two problems here. First it will need a rebase, because I renamed prefix_len_from_opt to opt_n. More importantly, you're changing the encoding of the variable from v6 style to v4-style. Which is fine... except you don't also change the other place that it's used (where -n is parsed before -a). TBH, if you want to change the encoding of this variable, I'd put it in a separate patch, so it doesn't get lost in this large one. > + > + for_each_addr(a, c->addrs, c->addr_count, AF_INET) { > + a->prefix_len = plen + 96; > + break; > + } > break; > } > case 'M': > @@ -1801,9 +1819,9 @@ void conf(struct ctx *c, int argc, char **argv) > > nl_sock_init(c, false); > if (!v6_only && !c->splice_only) > - c->ifi4 = conf_ip4(ifi4, &c->ip4); > + c->ifi4 = conf_ip4(c, ifi4); > if (!v4_only && !c->splice_only) > - c->ifi6 = conf_ip6(ifi6, &c->ip6); > + c->ifi6 = conf_ip6(c, ifi6); > > if (c->ifi4 && c->mtu < IPV4_MIN_MTU) { > warn("MTU %"PRIu16" is too small for IPv4 (minimum %u)", > @@ -1826,7 +1844,7 @@ void conf(struct ctx *c, int argc, char **argv) > if (!c->ifi4 && !v6_only) { > if (!c->splice_only) { > info("IPv4: no external interface as template, use local mode"); > - conf_ip4_local(&c->ip4); > + conf_ip4_local(c); > } > c->ifi4 = -1; > } > @@ -1834,7 +1852,7 @@ void conf(struct ctx *c, int argc, char **argv) > if (!c->ifi6 && !v4_only) { > if (!c->splice_only) { > info("IPv6: no external interface as template, use local mode"); > - conf_ip6_local(&c->ip6); > + conf_ip6_local(c); > } > c->ifi6 = -1; > } > @@ -1905,7 +1923,7 @@ void conf(struct ctx *c, int argc, char **argv) > if (!c->ifi6) { > c->no_ndp = 1; > c->no_dhcpv6 = 1; > - } else if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr)) { > + } else if (!fwd_get_addr(c, AF_INET6, CONF_ADDR_ANY, 0)) { > c->no_dhcpv6 = 1; > } > > diff --git a/dhcp.c b/dhcp.c > index 1ff8cba9..727485f7 100644 > --- a/dhcp.c > +++ b/dhcp.c > @@ -303,6 +303,7 @@ static void opt_set_dns_search(const struct ctx *c, size_t max_len) > int dhcp(const struct ctx *c, struct iov_tail *data) > { > char macstr[ETH_ADDRSTRLEN]; > + const struct guest_addr *a; > size_t mlen, dlen, opt_len; > struct in_addr mask, dst; > struct ethhdr eh_storage; > @@ -313,8 +314,10 @@ int dhcp(const struct ctx *c, struct iov_tail *data) > const struct udphdr *uh; > struct msg m_storage; > struct msg const *m; > + struct in_addr addr; > struct msg reply; > unsigned int i; > + int plen; > > eh = IOV_REMOVE_HEADER(data, eh_storage); > iph = IOV_PEEK_HEADER(data, iph_storage); > @@ -344,6 +347,14 @@ int dhcp(const struct ctx *c, struct iov_tail *data) > m->op != BOOTREQUEST) > return -1; > > + a = fwd_get_addr(c, AF_INET, CONF_ADDR_USER, 0); > + if (!a) > + a = fwd_get_addr(c, AF_INET, CONF_ADDR_ANY, 0); > + if (!a) > + return -1; > + > + addr = *inany_prefix_v4(&a->addr, a->prefix_len, &plen); > + I think an assert that inany_prefix_v4() returns non-NULL is probably a good idea. I doubt that static checkers will be able to reason that calling with AF_INET above means it must succeed here. > reply.op = BOOTREPLY; > reply.htype = m->htype; > reply.hlen = m->hlen; > @@ -352,7 +363,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data) > reply.secs = 0; > reply.flags = m->flags; > reply.ciaddr = m->ciaddr; > - reply.yiaddr = c->ip4.addr; > + reply.yiaddr = addr; > reply.siaddr = 0; > reply.giaddr = m->giaddr; > memcpy(&reply.chaddr, m->chaddr, sizeof(reply.chaddr)); > @@ -404,7 +415,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data) > > info(" from %s", eth_ntop(m->chaddr, macstr, sizeof(macstr))); > > - mask.s_addr = htonl(0xffffffff << (32 - c->ip4.prefix_len)); > + mask.s_addr = IN4_MASK(plen); > memcpy(opts[1].s, &mask, sizeof(mask)); > memcpy(opts[3].s, &c->ip4.guest_gw, sizeof(c->ip4.guest_gw)); > memcpy(opts[54].s, &c->ip4.our_tap_addr, sizeof(c->ip4.our_tap_addr)); > @@ -412,7 +423,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data) > /* If the gateway is not on the assigned subnet, send an option 121 > * (Classless Static Routing) adding a dummy route to it. > */ > - if ((c->ip4.addr.s_addr & mask.s_addr) > + if ((addr.s_addr & mask.s_addr) > != (c->ip4.guest_gw.s_addr & mask.s_addr)) { > /* a.b.c.d/32:0.0.0.0, 0:a.b.c.d */ > opts[121].slen = 14; > @@ -471,7 +482,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data) > if (m->flags & FLAG_BROADCAST) > dst = in4addr_broadcast; > else > - dst = c->ip4.addr; > + dst = addr; > > tap_udp4_send(c, c->ip4.our_tap_addr, 67, dst, 68, &reply, dlen); > > diff --git a/dhcpv6.c b/dhcpv6.c > index 29c7e320..f64cbc24 100644 > --- a/dhcpv6.c > +++ b/dhcpv6.c > @@ -318,7 +318,7 @@ static bool dhcpv6_opt(struct iov_tail *data, uint16_t type) > * false otherwise and @data is unmodified > */ > static bool dhcpv6_ia_notonlink(struct iov_tail *data, > - struct in6_addr *la) > + const struct in6_addr *la) > { > int ia_types[2] = { OPT_IA_NA, OPT_IA_TA }; > struct opt_ia_addr opt_addr_storage; > @@ -567,6 +567,7 @@ int dhcpv6(struct ctx *c, struct iov_tail *data, > struct opt_hdr client_id_storage; > /* cppcheck-suppress [variableScope,unmatchedSuppression] */ > struct opt_ia_na ia_storage; > + const struct guest_addr *a; > const struct in6_addr *src; > struct msg_hdr mh_storage; > const struct msg_hdr *mh; > @@ -574,6 +575,8 @@ int dhcpv6(struct ctx *c, struct iov_tail *data, > const struct udphdr *uh; > size_t mlen, n; > > + a = fwd_get_addr(c, AF_INET6, 0, CONF_ADDR_LINKLOCAL); > + > uh = IOV_REMOVE_HEADER(data, uh_storage); > if (!uh) > return -1; > @@ -627,7 +630,7 @@ int dhcpv6(struct ctx *c, struct iov_tail *data, > if (mh->type == TYPE_CONFIRM && server_id) > return -1; > > - if (dhcpv6_ia_notonlink(data, &c->ip6.addr)) { > + if (a && dhcpv6_ia_notonlink(data, &a->addr.a6)) { > > dhcpv6_send_ia_notonlink(c, saddr, data, > &client_id_base, > @@ -682,7 +685,8 @@ int dhcpv6(struct ctx *c, struct iov_tail *data, > resp.hdr.xid = mh->xid; > > tap_udp6_send(c, src, 547, saddr, 546, mh->xid, &resp, n); > - c->ip6.addr_seen = c->ip6.addr; > + if (a) > + c->ip6.addr_seen = a->addr.a6; > > return 1; > } > @@ -694,6 +698,7 @@ int dhcpv6(struct ctx *c, struct iov_tail *data, > void dhcpv6_init(const struct ctx *c) > { > time_t y2k = 946684800; /* Epoch to 2000-01-01T00:00:00Z, no mktime() */ > + const struct guest_addr *a; > uint32_t duid_time; > > duid_time = htonl(difftime(time(NULL), y2k)); > @@ -706,5 +711,7 @@ void dhcpv6_init(const struct ctx *c) > memcpy(resp_not_on_link.server_id.duid_lladdr, > c->our_tap_mac, sizeof(c->our_tap_mac)); > > - resp.ia_addr.addr = c->ip6.addr; > + a = fwd_get_addr(c, AF_INET6, 0, CONF_ADDR_LINKLOCAL); > + if (a) > + resp.ia_addr.addr = a->addr.a6; > } > diff --git a/fwd.c b/fwd.c > index 042158cf..f2ca34c2 100644 > --- a/fwd.c > +++ b/fwd.c > @@ -243,6 +243,61 @@ void fwd_neigh_table_init(const struct ctx *c) > fwd_neigh_table_update(c, &mga, c->our_tap_mac, true); > } > > +/** > + * fwd_set_addr() - Add or update an address in the unified address array > + * @c: Execution context > + * @addr: Address to add (IPv4-mapped or IPv6) > + * @flags: CONF_ADDR_* flags for this address > + * @prefix_len: Prefix length in IPv6 format (96-128 for IPv4-mapped) > + * > + * Find the first existing entry of the same address family and > + * overwrite it, or create a new one if none exists > + */ > +void fwd_set_addr(struct ctx *c, const union inany_addr *addr, > + uint8_t flags, int prefix_len) > +{ > + struct guest_addr *a; > + > + for_each_addr(a, c->addrs, c->addr_count, inany_af(addr)) { > + goto found; > + } > + > + if (c->addr_count >= MAX_GUEST_ADDRS) > + return; > + > + a = &c->addrs[c->addr_count++]; > + > +found: > + a->addr = *addr; > + a->prefix_len = prefix_len; > + a->flags = flags; > +} > + > +/** > + * fwd_get_addr() - Get guest address entry matching criteria > + * @c: Execution context > + * @af: Address family (AF_INET, AF_INET6, or AF_UNSPEC for any) > + * @incl: Required flags (any-match), CONF_ADDR_ANY for any > + * @excl: Flags that must not be present > + * > + * Return: first address entry matching criteria, or NULL > + */ > +const struct guest_addr *fwd_get_addr(const struct ctx *c, sa_family_t af, > + uint8_t incl, uint8_t excl) > +{ > + const struct guest_addr *a; > + > + for_each_addr(a, c->addrs, c->addr_count, af) { > + if (!(a->flags & incl)) > + continue; > + if (a->flags & excl) > + continue; > + return a; > + } > + > + return NULL; > +} > + > /* Forwarding table storage, generally accessed via pointers in struct ctx */ > static struct fwd_table fwd_in; > static struct fwd_table fwd_out; > @@ -794,8 +849,10 @@ static bool is_dns_flow(uint8_t proto, const struct flowside *ini) > * translation, false otherwise > */ > static bool fwd_guest_accessible4(const struct ctx *c, > - const struct in_addr *addr) > + const struct in_addr *addr) > { > + const struct guest_addr *a; > + > if (IN4_IS_ADDR_LOOPBACK(addr)) > return false; > > @@ -810,7 +867,8 @@ static bool fwd_guest_accessible4(const struct ctx *c, > /* For IPv4, addr_seen is initialised to addr, so is always a valid > * address > */ > - if (IN4_ARE_ADDR_EQUAL(addr, &c->ip4.addr) || > + a = fwd_get_addr(c, AF_INET, CONF_ADDR_ANY, 0); > + if ((a && IN4_ARE_ADDR_EQUAL(addr, inany_v4(&a->addr))) || > IN4_ARE_ADDR_EQUAL(addr, &c->ip4.addr_seen)) > return false; > > @@ -828,10 +886,13 @@ static bool fwd_guest_accessible4(const struct ctx *c, > static bool fwd_guest_accessible6(const struct ctx *c, > const struct in6_addr *addr) > { > + const struct guest_addr *a; > + > if (IN6_IS_ADDR_LOOPBACK(addr)) > return false; > > - if (IN6_ARE_ADDR_EQUAL(addr, &c->ip6.addr)) > + a = fwd_get_addr(c, AF_INET6, CONF_ADDR_ANY, 0); > + if (a && IN6_ARE_ADDR_EQUAL(addr, &a->addr.a6)) > return false; > > /* For IPv6, addr_seen starts unspecified, because we don't know what LL > @@ -876,16 +937,21 @@ static bool fwd_guest_accessible(const struct ctx *c, > static void nat_outbound(const struct ctx *c, const union inany_addr *addr, > union inany_addr *translated) > { > - if (inany_equals4(addr, &c->ip4.map_host_loopback)) > + const struct guest_addr *ga; > + > + if (inany_equals4(addr, &c->ip4.map_host_loopback)) { > *translated = inany_loopback4; > - else if (inany_equals6(addr, &c->ip6.map_host_loopback)) > + } else if (inany_equals6(addr, &c->ip6.map_host_loopback)) { > *translated = inany_loopback6; > - else if (inany_equals4(addr, &c->ip4.map_guest_addr)) > - *translated = inany_from_v4(c->ip4.addr); > - else if (inany_equals6(addr, &c->ip6.map_guest_addr)) > - translated->a6 = c->ip6.addr; > - else > + } else if (inany_equals4(addr, &c->ip4.map_guest_addr)) { > + ga = fwd_get_addr(c, AF_INET, CONF_ADDR_ANY, 0); > + *translated = ga ? ga->addr : inany_any4; > + } else if (inany_equals6(addr, &c->ip6.map_guest_addr)) { > + ga = fwd_get_addr(c, AF_INET6, CONF_ADDR_ANY, 0); > + translated->a6 = ga ? ga->addr.a6 : in6addr_any; > + } else { > *translated = *addr; > + } > } > > /** > @@ -990,16 +1056,23 @@ bool nat_inbound(const struct ctx *c, const union inany_addr *addr, > } else if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.map_host_loopback) && > inany_equals6(addr, &in6addr_loopback)) { > translated->a6 = c->ip6.map_host_loopback; > - } else if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.map_guest_addr) && > - inany_equals4(addr, &c->ip4.addr)) { > - *translated = inany_from_v4(c->ip4.map_guest_addr); > - } else if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.map_guest_addr) && > - inany_equals6(addr, &c->ip6.addr)) { > - translated->a6 = c->ip6.map_guest_addr; > - } else if (fwd_guest_accessible(c, addr)) { > - *translated = *addr; > } else { > - return false; > + const struct guest_addr *ga4, *ga6; > + > + ga4 = fwd_get_addr(c, AF_INET, CONF_ADDR_ANY, 0); > + ga6 = fwd_get_addr(c, AF_INET6, CONF_ADDR_ANY, 0); > + > + if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.map_guest_addr) && > + ga4 && inany_equals(addr, &ga4->addr)) { > + *translated = inany_from_v4(c->ip4.map_guest_addr); > + } else if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.map_guest_addr) && > + ga6 && inany_equals(addr, &ga6->addr)) { > + translated->a6 = c->ip6.map_guest_addr; > + } else if (fwd_guest_accessible(c, addr)) { > + *translated = *addr; > + } else { > + return false; > + } > } > > return true; > diff --git a/fwd.h b/fwd.h > index b60697d9..d677440f 100644 > --- a/fwd.h > +++ b/fwd.h > @@ -79,5 +79,9 @@ void fwd_neigh_table_free(const struct ctx *c, > void fwd_neigh_mac_get(const struct ctx *c, const union inany_addr *addr, > uint8_t *mac); > void fwd_neigh_table_init(const struct ctx *c); > +void fwd_set_addr(struct ctx *c, const union inany_addr *addr, > + uint8_t flags, int prefix_len); > +const struct guest_addr *fwd_get_addr(const struct ctx *c, sa_family_t af, > + uint8_t incl, uint8_t excl); > > #endif /* FWD_H */ > diff --git a/inany.h b/inany.h > index 6bf3ecaa..95756eb8 100644 > --- a/inany.h > +++ b/inany.h > @@ -102,6 +102,34 @@ static inline struct in_addr *inany_v4(const union inany_addr *addr) > return (struct in_addr *)&addr->v4mapped.a4; > } > > +/** inany_prefix_v4() - Extract IPv4 address and prefix length from inany > + * @addr: IPv4 (as mapped) or IPv6 address > + * @prefix_len: Prefix length in IPv6 format (96-128 for IPv4) > + * @v4_plen: Set to IPv4 prefix length (0-32) on success > + * > + * Return: IPv4 address if @addr is IPv4, NULL otherwise > + */ > +static inline struct in_addr *inany_prefix_v4(const union inany_addr *addr, > + int prefix_len, int *v4_plen) > +{ > + struct in_addr *v4 = inany_v4(addr); > + > + if (!v4) > + return NULL; > + *v4_plen = prefix_len - 96; > + return v4; > +} > + > +/** inany_af - Get address family of IPv[46] address > + * @addr: IPv4 or IPv6 address > + * > + * Return: AF_INET for IPv4, AF_INET6 for IPv6 > + */ > +static inline sa_family_t inany_af(const union inany_addr *addr) > +{ > + return inany_v4(addr) ? AF_INET : AF_INET6; > +} > + > /** inany_default_prefix_len() - Get default prefix length for address > * @addr: IPv4 or iPv6 address > * > diff --git a/ip.h b/ip.h > index aab9b86a..ac93c543 100644 > --- a/ip.h > +++ b/ip.h > @@ -19,6 +19,8 @@ > (ntohl(((struct in_addr *)(a))->s_addr) >> IN_CLASSA_NSHIFT == IN_LOOPBACKNET) > #define IN4_IS_ADDR_MULTICAST(a) \ > (IN_MULTICAST(ntohl(((struct in_addr *)(a))->s_addr))) > +#define IN4_MASK(prefix) \ > + ((prefix) <= 0 ? 0 : htonl(0xffffffff << (32 - (prefix)))) > #define IN4_ARE_ADDR_EQUAL(a, b) \ > (((struct in_addr *)(a))->s_addr == ((struct in_addr *)b)->s_addr) > #define IN4ADDR_LOOPBACK_INIT \ > diff --git a/ndp.c b/ndp.c > index 1f2bcb0c..a6a79055 100644 > --- a/ndp.c > +++ b/ndp.c > @@ -257,7 +257,6 @@ static void ndp_ra(const struct ctx *c, const struct in6_addr *dst) > .valid_lifetime = ~0U, > .pref_lifetime = ~0U, > }, > - .prefix = c->ip6.addr, > .source_ll = { > .header = { > .type = OPT_SRC_L2_ADDR, > @@ -265,8 +264,15 @@ static void ndp_ra(const struct ctx *c, const struct in6_addr *dst) > }, > }, > }; > + const struct guest_addr *a; > unsigned char *ptr = NULL; > > + a = fwd_get_addr(c, AF_INET6, CONF_ADDR_ANY, 0); Don't you need to exclude link local addresses? > + if (!a) > + return; > + > + ra.prefix = a->addr.a6; > + > ptr = &ra.var[0]; > > if (c->mtu) { > @@ -460,6 +466,7 @@ first: > */ > void ndp_send_init_req(const struct ctx *c) > { > + const struct guest_addr *a; > struct ndp_ns ns = { > .ih = { > .icmp6_type = NS, > @@ -468,8 +475,14 @@ void ndp_send_init_req(const struct ctx *c) > .icmp6_solicited = 0, /* Reserved */ > .icmp6_override = 0, /* Reserved */ > }, > - .target_addr = c->ip6.addr > + .target_addr = IN6ADDR_ANY_INIT > }; > + > + a = fwd_get_addr(c, AF_INET6, CONF_ADDR_ANY, 0); Again, don't you need to exclude linklocal, as the old code implicitly did? > + if (!a) > + return; > + > + ns.target_addr = a->addr.a6; > debug("Sending initial NDP NS request for guest MAC address"); > - ndp_send(c, &c->ip6.addr, &ns, sizeof(ns)); > + ndp_send(c, &a->addr.a6, &ns, sizeof(ns)); > } > diff --git a/passt.h b/passt.h > index 16506dcd..cafa35ea 100644 > --- a/passt.h > +++ b/passt.h > @@ -64,11 +64,29 @@ enum passt_modes { > MODE_VU, > }; > > +/* Maximum number of addresses in context address array */ > +#define MAX_GUEST_ADDRS 32 > + > +/** > + * struct guest_addr - Unified IPv4/IPv6 address entry > + * @addr: IPv4 (as mapped) or IPv6 address > + * @prefix_len: Prefix length in IPv6/IPv4-mapped [0,128]/[96,128] format > + * @flags: CONF_ADDR_* flags > + */ > +struct guest_addr { > + union inany_addr addr; > + uint8_t prefix_len; > + uint8_t flags; > +#define CONF_ADDR_USER BIT(0) /* User set via -a */ > +#define CONF_ADDR_HOST BIT(1) /* From host interface */ > +#define CONF_ADDR_GENERATED BIT(2) /* Generated by PASST/PASTA */ > +#define CONF_ADDR_LINKLOCAL BIT(3) /* Link-local address */ > +#define CONF_ADDR_ANY 0xff /* Match any flag */ In general I like CONF_ADDR_ANY instead of 0 being special-cased. But with LINKLOCAL in the mix it doesn't quite work. ANY meaning "USER or HOST or GENERATED" makes sense. ANY meaning "USER or HOST or GENERATED or LINKLOCAL" is nonsense. I suggest you move LINKLOCAL into a different field, as Stefano has suggested to handle this (maybe "provenance" for USER/HOST/GENERATED and "flags" for LINKLOCAL?). Or you could remove the LINKLOCAL flag from the structure entirely: the information is already present in the address itself. > +}; > + > /** > * struct ip4_ctx - IPv4 execution context > - * @addr: IPv4 address assigned to guest > * @addr_seen: Latest IPv4 address seen as source from tap > - * @prefixlen: IPv4 prefix length (netmask) > * @guest_gw: IPv4 gateway as seen by the guest > * @map_host_loopback: Outbound connections to this address are NATted to the > * host's 127.0.0.1 > @@ -87,9 +105,7 @@ enum passt_modes { > */ > struct ip4_ctx { > /* PIF_TAP addresses */ > - struct in_addr addr; > struct in_addr addr_seen; > - int prefix_len; > struct in_addr guest_gw; > struct in_addr map_host_loopback; > struct in_addr map_guest_addr; > @@ -110,7 +126,6 @@ struct ip4_ctx { > > /** > * struct ip6_ctx - IPv6 execution context > - * @addr: IPv6 address assigned to guest > * @addr_seen: Latest IPv6 global/site address seen as source from tap > * @addr_ll_seen: Latest IPv6 link-local address seen as source from tap > * @guest_gw: IPv6 gateway as seen by the guest > @@ -131,7 +146,6 @@ struct ip4_ctx { > */ > struct ip6_ctx { > /* PIF_TAP addresses */ > - struct in6_addr addr; > struct in6_addr addr_seen; > struct in6_addr addr_ll_seen; > struct in6_addr guest_gw; > @@ -190,6 +204,8 @@ struct ip6_ctx { > * @fqdn: Guest FQDN > * @ifi6: Template interface for IPv6, -1: none, 0: IPv6 disabled > * @ip6: IPv6 configuration > + * @addrs: Unified address array for both IPv4 (mapped) and IPv6 > + * @addr_count: Number of active entries in @addrs array > * @pasta_ifn: Name of namespace interface for pasta > * @pasta_ifi: Index of namespace interface for pasta > * @pasta_conf_ns: Configure namespace after creating it > @@ -273,6 +289,9 @@ struct ctx { > int ifi6; > struct ip6_ctx ip6; > > + struct guest_addr addrs[MAX_GUEST_ADDRS]; > + int addr_count; > + > char pasta_ifn[IF_NAMESIZE]; > unsigned int pasta_ifi; > int pasta_conf_ns; > @@ -317,6 +336,41 @@ struct ctx { > > extern struct ctx passt_ctx; > > +/** > + * next_addr_idx_() - Find next address index matching family filter > + * @addrs: Array of guest addresses > + * @count: Number of addresses in array > + * @i: Starting index > + * @af: Address family filter: AF_INET, AF_INET6, or AF_UNSPEC for all > + * > + * Return: next matching index, or count if none found > + */ > +static inline int next_addr_idx_(const struct guest_addr *addrs, int count, > + int i, sa_family_t af) > +{ > + for (; i < count; i++) { > + sa_family_t entry_af; > + > + entry_af = inany_v4(&addrs[i].addr) ? AF_INET : AF_INET6; You can reuse inany_af() here. > + > + if (af == AF_UNSPEC || af == entry_af) > + return i; > + } > + return i; > +} > + > +/** > + * for_each_addr() - Iterate over addresses in array > + * @a: Pointer variable for current entry (struct guest_addr *) > + * @addrs: Array of guest addresses (e.g., c->addrs) > + * @count: Number of addresses (e.g., c->addr_count) > + * @af: Address family filter: AF_INET, AF_INET6, or 0 for all > + */ > +#define for_each_addr(a, addrs, count, af) \ > + for (int i_ = next_addr_idx_((addrs), (count), 0, (af)); \ > + i_ < (count) && ((a) = &(addrs)[i_], true); \ > + i_ = next_addr_idx_((addrs), (count), i_ + 1, (af))) > + > void proto_update_l2_buf(const unsigned char *eth_d); > > #endif /* PASST_H */ > diff --git a/pasta.c b/pasta.c > index 4e7ee542..9ef3ac00 100644 > --- a/pasta.c > +++ b/pasta.c > @@ -330,6 +330,8 @@ void pasta_ns_conf(struct ctx *c) > > if (c->pasta_conf_ns) { > unsigned int flags = IFF_UP; > + const struct guest_addr *a; > + int plen = 0; > > if (c->mtu) > nl_link_set_mtu(nl_sock_ns, c->pasta_ifi, c->mtu); > @@ -341,10 +343,17 @@ void pasta_ns_conf(struct ctx *c) > > if (c->ifi4) { Nit: I think you can reduce the very deep nesting here, by moving the fwd_get_addr() and changing the if below to.. > if (c->ip4.no_copy_addrs) { .. if (no_copy_addrs && a && (v4 = inany_v4(a...))) It means the address search will happen even when we don't need it, but it's once per startup, so we don't really care. > - rc = nl_addr_set(nl_sock_ns, c->pasta_ifi, > - AF_INET, > - &c->ip4.addr, > - c->ip4.prefix_len); > + a = fwd_get_addr(c, AF_INET, CONF_ADDR_ANY, 0); > + if (a) { > + const struct in_addr *v4; > + > + v4 = inany_prefix_v4(&a->addr, > + a->prefix_len, > + &plen); > + rc = nl_addr_set(nl_sock_ns, > + c->pasta_ifi, AF_INET, > + v4, plen); > + } > } else { > rc = nl_addr_dup(nl_sock, c->ifi4, > nl_sock_ns, c->pasta_ifi, > @@ -397,11 +406,12 @@ ipv4_done: > 0, IFF_NOARP); > > if (c->ip6.no_copy_addrs) { I think a similar transformation should be possible here. > - if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr)) { > + a = fwd_get_addr(c, AF_INET6, CONF_ADDR_ANY, 0); > + if (a) > rc = nl_addr_set(nl_sock_ns, > - c->pasta_ifi, AF_INET6, > - &c->ip6.addr, 64); > - } > + c->pasta_ifi, > + AF_INET6, &a->addr.a6, > + a->prefix_len); > } else { > rc = nl_addr_dup(nl_sock, c->ifi6, > nl_sock_ns, c->pasta_ifi, > diff --git a/tap.c b/tap.c > index d4189617..12630f58 100644 > --- a/tap.c > +++ b/tap.c > @@ -1005,8 +1005,12 @@ resume: > c->ip6.addr_seen = *saddr; > } > > - if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr)) > - c->ip6.addr = *saddr; > + if (!c->ip6.addr_fixed && This addr_fixed check is unnnecessary - addr_fixed can only be set if an address is specified, so the fwd_get_addr() below can't fail. > + !fwd_get_addr(c, AF_INET6, CONF_ADDR_ANY, 0)) { > + union inany_addr addr = { .a6 = *saddr }; > + > + fwd_set_addr(c, &addr, CONF_ADDR_LINKLOCAL, 64); > + } > } else if (!c->ip6.addr_fixed && > !IN6_IS_ADDR_UNSPECIFIED(saddr)) { > c->ip6.addr_seen = *saddr; > -- > 2.52.0 > -- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson