Re: [PATCH 09/12] conf: Move address configuration into helper function

On Fri, 26 Jun 2026 17:10:00 +1000 David Gibson wrote:

The handling of the -a option is getting complex enough that it's pretty bulky inside it's switch label. Move it into a new conf_addr() function.

Nit if you respin: 'its'.

We also rename the bulky addr_has_prefix_len and prefix_len_from_opt variables to the terser 'opt_a_is_prefix' and 'opt_n', since they are specifically about those command line options.

Cc: Jon Maloy

Signed-off-by: David Gibson --- conf.c | 96 ++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 53 insertions(+), 43 deletions(-)

diff --git a/conf.c b/conf.c index 2d1895d4..3614776c 100644 --- a/conf.c +++ b/conf.c @@ -1168,6 +1168,53 @@ int conf_tap_fd(const char *arg) return val; }

+/** + * conf_addr() - Configure guest address with -a option + * @c: Execution context + * @arg: -a command line argument + * @opt_n: Value from -n option, if any + */ +static bool conf_addr(struct ctx *c, char *arg, uint8_t opt_n) +{ + union inany_addr addr; + 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 (inany_is_unspecified(&addr) || inany_is_multicast(&addr) || + inany_is_loopback(&addr) || IN6_IS_ADDR_V4COMPAT(&addr.a6)) + die("Invalid address: %s", arg); + + if (inany_v4(&addr)) { + c->ip4.addr = *inany_v4(&addr); + c->ip4.prefix_len = prefix_len - 96; + c->ip4.addr_fixed = true; + if (c->mode == MODE_PASTA) + 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; + } + + return is_prefix; +} + /** * conf() - Process command-line arguments and set configuration * @c: Execution context @@ -1262,12 +1309,12 @@ void conf(struct ctx *c, int argc, char **argv) unsigned dns4_idx = 0, dns6_idx = 0; unsigned long max_mtu = IP_MAX_MTU; struct fqdn *dnss = c->dns_search; - bool addr_has_prefix_len = false; - uint8_t prefix_len_from_opt = 0; unsigned int ifi4 = 0, ifi6 = 0; + bool opt_a_is_prefix = false; const char *logfile = NULL; char *runas = NULL; size_t logsize = 0; + uint8_t opt_n = 0; int name, ret; uid_t uid; gid_t gid; @@ -1567,52 +1614,15 @@ void conf(struct ctx *c, int argc, char **argv) c->mtu = mtu; break; } - case 'a': { - union inany_addr addr; - uint8_t prefix_len; - - addr_has_prefix_len = inany_prefix_pton(optarg, &addr, - &prefix_len); - - if (addr_has_prefix_len && prefix_len_from_opt) - die("Redundant prefix length specification"); - - p = optarg; - if (!addr_has_prefix_len && - !(parse_inany(&p, &addr) && parse_eoi(p))) - die("Invalid address: %s", optarg); - - if (prefix_len_from_opt && inany_v4(&addr)) - prefix_len = prefix_len_from_opt; - else if (!addr_has_prefix_len) - 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", optarg); - - if (inany_v4(&addr)) { - c->ip4.addr = *inany_v4(&addr); - c->ip4.prefix_len = prefix_len - 96; - c->ip4.addr_fixed = true; - if (c->mode == MODE_PASTA) - 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; - } + case 'a': + opt_a_is_prefix = conf_addr(c, optarg, opt_n); break; - } case 'n': - if (addr_has_prefix_len) + if (opt_a_is_prefix) die("Redundant prefix length specification");

c->ip4.prefix_len = conf_ip4_prefix(optarg); - prefix_len_from_opt = c->ip4.prefix_len + 96; + opt_n = c->ip4.prefix_len + 96; break; case 'M': parse_mac(c->our_tap_mac, optarg);

-- Stefano