Problem - Kevin Tafuro

Access restriction information read by spc_host_init( ) is required to be in a very
specific format. Whitespace is mostly ignored, and lines beginning with a hash mark
(#) or a semicolon (;) are considered comments and ignored. Any other line in the
file must begin with either “allow:” or “deny:” to indicate the type of rule.
Following the rule type is a whitespace-separated list of addresses that are to be
either allowed or denied access. Addresses may be hostnames or IP addresses. IP
addresses may be specified as an address and mask or simply as an address. In the
former case, the address may contain up to four parts, where each part must be
expressed in decimal (ranging from 0 to 255), and a period (.) must be used to separate
them. A forward slash (/) separates the address from the mask, and the mask is
expressed as the number of bits to set. Table 8-1 lists example representations that
are accepted as valid.
Table 8-1. Example address representations accepted by spc_host_init( )
Representation Meaning
www.oreilly.com The host to which the reverse-and-forward
maps www.oreilly.com will be matched.
12.109.142.4 Only the specific address 12.109.142.4 will be
matched.
10/24 Any address starting with 10 will be matched.
192.168/16 Any address starting with 192.168 will be
matched.
If any errors are encountered when parsing the access restriction data file, a message
containing the name of the file and the line number is printed. Parsing of the file then
continues on the next line. Fatal errors (e.g., out of memory) are also noted in a similar
fashion, but parsing terminates immediately and any data successfully parsed so
far is thrown away.
When spc_host_init( ) completes successfully (even if parse errors are encountered),
it will return 1; otherwise, it will return 0.
#define SPC_HOST_ALLOW 1
#define SPC_HOST_DENY 0
typedef struct {
int action;
char *name;
in_addr_t addr;
in_addr_t mask;
} spc_hostrule_t;
static int spc_host_rulecount;
static spc_hostrule_t *spc_host_rules;
static int add_rule(spc_hostrule_t *rule) {
spc_hostrule_t *tmp;
382 | Chapter 8: Authentication and Key Exchange
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