From: Stefano Brivio <sbrivio@redhat.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: passt-dev@passt.top, Jon Maloy <jmaloy@redhat.com>
Subject: Re: [PATCH 10/12] conf: Use new parsing tools to handle -a option
Date: Wed, 01 Jul 2026 02:07:50 +0200 (CEST) [thread overview]
Message-ID: <20260701020750.765493ee@elisabeth> (raw)
In-Reply-To: <20260626071003.3472194-11-david@gibson.dropbear.id.au>
On Fri, 26 Jun 2026 17:10:01 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:
> The -a command line option can take either an address prefix, or a bare
> address. Current parsing of this is pretty awkward, using the special
> purpose helper inany_prefix_pton(). With the new incremental parsing
> helpers this can be done more naturally. Rework it to use them.
>
> This does requiring extending parse_inany() to parse_inany_() which also
> reports the format of the address as parse, as opposed to the family of
> the resulting address. This is so that ::ffff:192.0.1.1/112 will be
> correctly interpreted the same as 192.0.1.1/16, rather than the
> nonsensical 192.0.0.1/112.
By the way, as far as I know, ::ffff:192.0.1.1/112 is not a valid
address, because IPv4-mapped addresses must always have /96 as prefix
length (see RFC 6890, Table 20).
RFC 6052 adds some madness (e.g. 2001:db8:122:344::192.0.2.33 from
Table 1) on top, but as far as I understand you can't use that for
prefixes.
>
> Cc: Jon Maloy <jmaloy@redhat.com>
>
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
> Makefile | 1 -
> conf.c | 63 +++++++++++++++++++++++++++++++++++---------------------
> inany.c | 50 --------------------------------------------
> inany.h | 2 --
> parse.c | 17 ++++++++++++---
> parse.h | 5 ++++-
> 6 files changed, 58 insertions(+), 80 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index e2b22ddf..5757aeff 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -223,7 +223,6 @@ passt-repair.cppcheck: $(PASST_REPAIR_SRCS) $(PASST_REPAIR_HEADERS) seccomp_repa
> pesto.cppcheck: BASE_CPPFLAGS += -DPESTO
> pesto.cppcheck: CPPCHECK_FLAGS += --suppress=unusedFunction:bitmap.c
> pesto.cppcheck: CPPCHECK_FLAGS += --suppress=unusedFunction:inany.h
> -pesto.cppcheck: CPPCHECK_FLAGS += --suppress=unusedFunction:inany.c
> pesto.cppcheck: CPPCHECK_FLAGS += --suppress=unusedFunction:ip.h
> pesto.cppcheck: CPPCHECK_FLAGS += --suppress=unusedFunction:serialise.c
> pesto.cppcheck: CPPCHECK_FLAGS += --suppress=staticFunction:fwd_rule.c
> diff --git a/conf.c b/conf.c
> index 3614776c..ff7ca5c7 100644
> --- a/conf.c
> +++ b/conf.c
> @@ -1176,43 +1176,60 @@ int conf_tap_fd(const char *arg)
> */
> static bool conf_addr(struct ctx *c, char *arg, uint8_t opt_n)
> {
> + unsigned long prefix_len;
> + const struct in_addr *a4;
> union inany_addr addr;
> + sa_family_t parseaf;
I think parse_af would be more readable (and also more consistent with
e.g. prefix_len).
> const char *p = arg;
> - uint8_t prefix_len;
> bool is_prefix;
>
> - is_prefix = inany_prefix_pton(arg, &addr, &prefix_len);
> -
> - if (is_prefix && opt_n)
> - die("Redundant prefix length specification");
> -
> - if (!is_prefix &&
> - !(parse_inany(&p, &addr) && parse_eoi(p)))
> - die("Invalid address: %s", arg);
> -
> - if (opt_n && inany_v4(&addr))
> - prefix_len = opt_n;
> - else if (!is_prefix)
> - prefix_len = inany_default_prefix_len(&addr);
> + if (!parse_inany_(&p, &addr, &parseaf))
...just call it af? It doesn't matter so much in the following code
where that comes from. Starting from here, we know it's the address
family we're using.
> + goto bad;
> + a4 = inany_v4(&addr);
> +
> + if ((is_prefix = parse_literal(&p, "/"))) {
The current return convention makes more sense here, but I wouldn't
find:
is_prefix = !parse_literal(&p, "/")
outrageous, either.
> + /* Prefix length included in -a option */
> + if (!parse_unsigned(&p, 10, &prefix_len))
> + goto bad;
> + if (opt_n)
> + die("Redundant prefix length specification");
> + if (parseaf == AF_INET) {
> + if (prefix_len > 32)
> + goto bad_prefix;
> + prefix_len += 96;
> + } else if (prefix_len > 128) {
> + goto bad_prefix;
> + }
> + } else {
> + /* Get prefix length from elsewhere */
> + if (opt_n && a4)
> + prefix_len = opt_n;
> + else
> + prefix_len = inany_default_prefix_len(&addr);
> + }
>
> - if (inany_is_unspecified(&addr) || inany_is_multicast(&addr) ||
> - inany_is_loopback(&addr) || IN6_IS_ADDR_V4COMPAT(&addr.a6))
> - die("Invalid address: %s", arg);
> + if (!parse_eoi(p) ||
Note: with *p instead of !parse_eoi(), this would fit on one line.
> + !inany_is_unicast(&addr) ||
> + inany_is_loopback(&addr))
> + goto bad;
>
> - if (inany_v4(&addr)) {
> - c->ip4.addr = *inany_v4(&addr);
> + if (a4) {
> + c->ip4.addr = *a4;
> c->ip4.prefix_len = prefix_len - 96;
> c->ip4.addr_fixed = true;
> - if (c->mode == MODE_PASTA)
Why does this (and the same condition just below) go away here? I mean,
it's not fundamental in any case, but changing it here makes it look
like it has something to do with this change (and I guess it's not the
case).
> - c->ip4.no_copy_addrs = true;
> + c->ip4.no_copy_addrs = true;
> } else {
> c->ip6.addr = addr.a6;
> c->ip6.addr_fixed = true;
> - if (c->mode == MODE_PASTA)
> - c->ip6.no_copy_addrs = true;
> + c->ip6.no_copy_addrs = true;
> }
>
> return is_prefix;
> +
> +bad_prefix:
> + die("Invalid prefix length: %s", arg);
> +bad:
> + die("Invalid guest address: %s", arg);
> }
>
> /**
> diff --git a/inany.c b/inany.c
> index 154f08b5..120c9387 100644
> --- a/inany.c
> +++ b/inany.c
> @@ -70,53 +70,3 @@ const char *inany_ntop(const union inany_addr *src, char *dst, socklen_t size)
>
> return inet_ntop(AF_INET6, &src->a6, dst, size);
> }
> -
> -/**
> - * inany_prefix_pton() - Parse an IPv[46] address with prefix length
> - * @src: IPv[46] address and prefix length string in CIDR format
> - * @dst: Output buffer, filled with parsed address
> - * @prefix_len: Prefix length, to be filled in IPv6 format
> - *
> - * Return: 1 on success, 0 if no parseable address or prefix is found
> - */
> -int inany_prefix_pton(const char *src, union inany_addr *dst,
> - uint8_t *prefix_len)
> -{
> - char astr[INANY_ADDRSTRLEN] = { 0 };
> - size_t alen = strcspn(src, "/");
> - const char *pstr = &src[alen + 1];
> - const char *p = astr;
> - unsigned long plen;
> - char *end;
> -
> - if (alen >= INANY_ADDRSTRLEN)
> - return 0;
> -
> - if (src[alen] != '/')
> - return 0;
> -
> - strncpy(astr, src, alen);
> -
> - /* Read prefix length */
> - errno = 0;
> - plen = strtoul(pstr, &end, 10);
> - if (errno || *end || plen > 128)
> - return 0;
> -
> - /* Read address */
> - if (inet_pton(AF_INET6, astr, dst)) {
> - if (inany_v4(dst) && plen < 96)
> - return 0;
> - *prefix_len = plen;
> - return 1;
> - }
> -
> - if (parse_inany(&p, dst) && parse_eoi(p)) {
> - if (plen > 32)
> - return 0;
> - *prefix_len = plen + 96;
> - return 1;
> - }
> -
> - return 0;
> -}
> diff --git a/inany.h b/inany.h
> index 93d98368..5b176ccf 100644
> --- a/inany.h
> +++ b/inany.h
> @@ -303,7 +303,5 @@ static inline int inany_from_sockaddr(union inany_addr *dst, in_port_t *port,
>
> bool inany_matches(const union inany_addr *a, const union inany_addr *b);
> const char *inany_ntop(const union inany_addr *src, char *dst, socklen_t size);
> -int inany_prefix_pton(const char *src, union inany_addr *dst,
> - uint8_t *prefix_len);
>
> #endif /* INANY_H */
> diff --git a/parse.c b/parse.c
> index 0349c5dc..3e0dbd45 100644
> --- a/parse.c
> +++ b/parse.c
> @@ -184,18 +184,29 @@ static bool parse_ipv6(const char **cursor, struct in6_addr *abuf)
> }
>
> /**
> - * parse_inany() - Parse an IPv4 or IPv6 address from a string
> + * parse_inany_() - Parse an IPv4 or IPv6 address from a string
> * @addr: On success, updated with parsed address
> + * @parseaf: On success, updated with the format of the parsed address
> + *
> + * @parseaf is updated to reflect the string format, not the final address
> + * family. So "::ffff:192.0.1.1", will set @parseaf to AF_INET6, despite being
> + * a IPv4-mapped address.
> */
> -bool parse_inany(const char **cursor, union inany_addr *addr)
> +bool parse_inany_(const char **cursor, union inany_addr *addr,
> + sa_family_t *parseaf)
> {
> struct in_addr a4;
>
> - if (parse_ipv6(cursor, &addr->a6))
> + if (parse_ipv6(cursor, &addr->a6)) {
> + if (parseaf)
> + *parseaf = AF_INET6;
> return true;
> + }
>
> if (parse_ipv4(cursor, &a4)) {
> *addr = inany_from_v4(a4);
> + if (parseaf)
> + *parseaf = AF_INET;
> return true;
> }
>
> diff --git a/parse.h b/parse.h
> index 2820a065..08b038cf 100644
> --- a/parse.h
> +++ b/parse.h
> @@ -27,6 +27,9 @@ bool parse_eoi(const char *cursor);
> bool parse_unsigned(const char **cursor, int base, unsigned long *valp);
> bool parse_port_range(const char **cursor, struct port_range *range);
> bool parse_ipv4(const char **cursor, struct in_addr *abuf);
> -bool parse_inany(const char **cursor, union inany_addr *addr);
> +bool parse_inany_(const char **cursor, union inany_addr *addr,
> + sa_family_t *parseaf);
> +
> +#define parse_inany(cursor, addr) parse_inany_((cursor), (addr), NULL)
>
> #endif /* _PARSE_H */
--
Stefano
next prev parent reply other threads:[~2026-07-01 0:07 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-26 7:09 [PATCH 00/12] Rework option parsing in preparation for destination remapping David Gibson
2026-06-26 7:09 ` [PATCH 01/12] Makefile: Add missing PESTO_HEADERS variable David Gibson
2026-07-01 0:07 ` Stefano Brivio
2026-07-01 1:23 ` David Gibson
2026-06-26 7:09 ` [PATCH 02/12] conf: Use parameter instead of global in conf_nat() David Gibson
2026-07-01 0:07 ` Stefano Brivio
2026-07-01 1:24 ` David Gibson
2026-06-26 7:09 ` [PATCH 03/12] parse: Start splitting out parsing helpers David Gibson
2026-07-01 0:07 ` Stefano Brivio
2026-07-01 1:36 ` David Gibson
2026-06-26 7:09 ` [PATCH 04/12] conf: Remove duplicate parsing of -F option David Gibson
2026-06-26 7:09 ` [PATCH 05/12] conf: Clean up conf_ip4_prefix() David Gibson
2026-06-26 7:09 ` [PATCH 06/12] parse: Add helper to parse unsigned integer values David Gibson
2026-06-26 7:09 ` [PATCH 07/12] parse: Move parse_port_range() to new parsing framework David Gibson
2026-06-26 7:09 ` [PATCH 08/12] parse: Add helpers for parsing IP addresses David Gibson
2026-07-01 0:07 ` Stefano Brivio
2026-07-01 0:09 ` [RESEND] " Stefano Brivio
2026-07-01 0:11 ` [RESEND #2] " Stefano Brivio
2026-07-01 1:44 ` David Gibson
2026-07-01 1:43 ` David Gibson
2026-06-26 7:10 ` [PATCH 09/12] conf: Move address configuration into helper function David Gibson
2026-07-01 0:07 ` Stefano Brivio
2026-07-01 1:44 ` David Gibson
2026-06-26 7:10 ` [PATCH 10/12] conf: Use new parsing tools to handle -a option David Gibson
2026-07-01 0:07 ` Stefano Brivio [this message]
2026-07-01 1:55 ` David Gibson
2026-06-26 7:10 ` [PATCH 11/12] fwd_rule: Allow "all" port specs to be combined with other options David Gibson
2026-07-01 0:07 ` Stefano Brivio
2026-07-01 1:55 ` David Gibson
2026-06-26 7:10 ` [PATCH 12/12] fwd_rule: Rewrite forward rule parsing using parse.c helpers David Gibson
2026-07-01 0:08 ` Stefano Brivio
2026-07-01 3:03 ` David Gibson
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