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2022-03-15resolv: make OS X compatibleJo-Philipp Wich
OS X `socket()` does not support the `SOCK_NONBLOCK` or `SOCK_CLOEXEC` constants, so apply these flags using `fcntl()` after creating the socket. Signed-off-by: Jo-Philipp Wich <jo@mein.io>
2022-01-18lib: replace usages of vasprintf() with xvasprintf()Jo-Philipp Wich
This avoid triggering -Werror=unused-result compilation failures with certain toolchains. Signed-off-by: Jo-Philipp Wich <jo@mein.io>
2021-10-22lib: introduce resolver libraryJo-Philipp Wich
This adds a simple, UDP-only DNS resolver library mimicking the operation of the extended busybox nslookup applet. Simply querying a domain name will perform A + AAAA resolving by default: # ucode -mresolv -Rs 'printf("%.J\n", resolv.query("example.com"))' { "example.com": { "A": [ "93.184.216.34" ], "AAAA": [ "2606:2800:220:1:248:1893:25c8:1946" ] } } Passing IP addresses will automatically perform PTR requests: # ucode -mresolv -Rs 'printf("%.J\n", resolv.query("8.8.8.8"))' { "8.8.8.8.in-addr.arpa": { "PTR": [ "dns.google" ] } } # ucode -mresolv -Rs 'printf("%.J\n", resolv.query("2001:4860:4860::8888"))' { "8.8.8.8.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.6.8.4.0.6.8.4.1.0.0.2.ip6.arpa": { "PTR": [ "dns.google" ] } } Additional options for query type and nameserver selection can be passed via a second optional options dictionary: # ucode -mresolv -Rs 'printf("%.J\n", resolv.query([ "openwrt.org", "example.org", "doesnotexist.tld" ], { type: [ "A", "AAAA", "MX" ], nameserver: [ "1.1.1.1", "8.8.4.4" ], timeout: 5000, retries: 2, edns_maxsize: 4096 }))' { "openwrt.org": { "A": [ "139.59.209.225" ], "MX": [ [ 10, "util-01.infra.openwrt.org" ] ], "AAAA": [ "2a03:b0c0:3:d0::1af1:1" ] }, "example.org": { "A": [ "93.184.216.34" ], "AAAA": [ "2606:2800:220:1:248:1893:25c8:1946" ], "MX": [ [ 0, "." ] ] }, "doesnotexist.tld": { "rcode": "NXDOMAIN" } } Signed-off-by: Jo-Philipp Wich <jo@mein.io>