--- name: "cidr" section: "3bobcat" platform: "linux" package: "libbobcat-dev" version: "6.07.01-2" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/cidr" --- # cidr(3bobcat) Compares IP4 addresses to CIDR specifications ## NAME FBB::Cidr - Compares IP4 addresses to CIDR specifications ## SYNOPSIS **#include \**\ Linking option: *-lbobcat* ## DESCRIPTION Objects of the class *Cidr* can be used for testing whether IP4 Internet addresses belong to address ranges defined by Classless Inter-Domain Routing (CIDR) address block specifications. CIDR blocks are specified as *a.b.c.d/m* where *a.b.c.d* are the four octets of a dotted decimal IP4 address specification (e.g., 129.125.14.80) and *m* is a mask-size (ranging from 0 to 32) defining the number of most significant bits to remain as-is. The CIDR specification 129.125.14.80/16 defines a class B network, with addresses ranging from 129.125.0.0 to 129.125.255.255. The mask size does not have to be a multiple of 8. E.g., when specifying 129.125.14.80/5 only the most significant 5 bits of the first octed are fixed, resulting in an address range ranging from 128.0.0.0 to 135.255.255.255. CIDR specifications passed to a *Cidr* object must be of the form *a.b.c.d* or *a.b.c.d/m*. If the mask is not specified a mask-size of 32 is used, effectively defining an address range of only one address. Mask values of 0 are ignored. Mask values of 0 are ignored by *Cidr* objects. When specifying CIDRs on a stream, empty lines and comment lines (having a hash-character (#) as their first non-blank character) are ignored. Non-empty lines must start with a CIDR specification, and the *Cidr* object will ignore all information on a line trailing a CIDR specification. ## NAMESPACE **FBB**\ All constructors, members, operators and manipulators, mentioned in this man-page, are defined in the namespace **FBB**. ## INHERITS FROM \- ## CONSTRUCTORS - o **Cidr(std::string const &cidrPattern)**:\ The *Cidr* object is initialized with a single CIDR specification. - - o **Cidr(std::istream &cidrStream)**:\ The *Cidr* object is initialized with CIDR specifications read from the *std::istream cidrStream*. Default, copy and move constructors and the copy and move assignment operators are available. ## MEMBER FUNCTIONS The return valuess of the accessors (i.e., the *const* members) are only defined following a successful match (see below, the *match* members). - o **std::string const &address() const**:\ returns the address matching a CIDR. - - o **std::string cidr() const**:\ returns the CIDR containing a specified address. - - o **std::string first() const**:\ returns the first address of the range of addresses defined by the CIDR specification. - - o **std::string last() const**:\ returns the last address of the range of addresses defined by the CIDR specification. Note that *first, last* do not define an iterator range. The address returned by *last* still belongs to the CIDR-range. - - o **bool match(std::istream &in)**:\ The value *true* is returned when an IP4 address found in the lines of *in* belongs to a CIDR range inspected by the *Cidr* object. The *match* function returns *true* at the first matching address. E.g., if a line contains the text ``` This is address 1.2.3.4 and this is 5.6.7.8 ``` and the CIDR specifications ``` 5.1.1.1/8 1.2.1.1/16 ``` were provided to the *Cidr* object, then the object will report a match for *5.6.7.8*. - As soon as a match is found *match* returns *true*. If none of the addresses found in the lines of *in* matches any of the object’s CIDR specifications, *false* is returned. - - o **std::string mask() const**:\ returns the mask used by the *CIDR* specification. - - o **bool match(std::string const &line)**:\ The value *true* is returned when an IP4 address found in *line* belongs to a CIDR range inspected by the *Cidr* object. The *match* function returns *true* at the first matching address. - If none of the addresses found in *line* matches any of the object’s CIDR specifications, *false* is returned. - - o **void setCidr(std::istream &cidrStream)**:\ A new set of CIDR specification is loaded into the *Cidr* object, reading the specifications from *cidrStream*. - - o **void setCidr(std::string const &cidrPattern)**:\ A new CIDR specification is loaded into the *Cidr* object, using the specification found in *cidrPattern*. The *Cidr* object is initialized with a single CIDR specification which must be of the form *a.b.c.d* or *a.b.c.d/m*. If the mask is not specified a mask-size of 32 is used, effectively defining an address range of only one address. Mask values of 0 are ignored. - - o **void swap(Cidr &other)**:\ The current and *other* object are swapped. ## STATIC MEMBERS - o **size\_t dotted2binary(std::string const &dotted)**:\ Converts "a.b.c.d" to a 32-bits value - - o **std::string binary2dotted(size\_t binary)**:\ Converts a 32-bits value to a dotted decimal IP4 address ## EXAMPLE ``` #include #include #include #ifdef BOBCAT #include #else #include "cidr" #endif using namespace std; using namespace FBB; int main(int argc, char **argv) { enum Spec { NONE, FILE, CIN }; Spec spec = CIN; ifstream in; if (argc > 1) { Exception::open(in, argv[1]); // file containing cidr-specs spec = FILE; } while (true) { string cidrSpec; if (spec == CIN) { cout << "Specify cidr (empty to quit): "; if (!getline(cin, cidrSpec) || cidrSpec.empty()) break; } try { Cidr cidr; switch (spec) { case NONE: return 0; case FILE: cidr.setCidr(in); spec = NONE; break; case CIN: cidr.setCidr(cidrSpec); } while (true) { cout << "Specify address to test (empty to " << (spec == CIN ? "respec. CIDR" : "quit") << "): "; string address; if (!getline(cin, address) || address.empty()) break; if (!cidr.match(address)) { cout << "Address " << address << " not in "; if (spec == CIN) cout << cidrSpec << ’\n’; else cout << "specifications in " << argv[1] << ’\n’; } else cout << "Address " << address << " in " << cidr.cidr() << "\n" "Lowest address: " << cidr.first() << "\n" "Highest address: " << cidr.last() << "\n" "CIDR mask: " << cidr.mask() << "\n" "Address: " << cidr.address() << ’\n’; } } catch (exception const &err) { cout << "Oops... " << err.what() << "\n" "Try again...\n"; } } } ``` ## FILES *bobcat/cidr* - defines the class interface ## SEE ALSO [**bobcat**(7)](/bobcat/7.md) ## BUGS Members of *Cidr* use static data. The current implementation of *Cidr* is therefore not thread-safe. ## BOBCAT PROJECT FILES - o *https://fbb-git.gitlab.io/bobcat/*: gitlab project page; Debian Bobcat project files: - o *libbobcat6*: debian package containing the shared library, changelog and copyright note; - o *libbobcat-dev*: debian package containing the static library, headers, manual pages, and developer info; ## BOBCAT Bobcat is an acronym of \`Brokken’s Own Base Classes And Templates’. ## COPYRIGHT This is free software, distributed under the terms of the GNU General Public License (GPL). ## AUTHOR Frank B. Brokken (**f.b.brokken@rug.nl**).