diff options
Diffstat (limited to 'freebsd/sbin/dhclient/options.c')
| -rw-r--r-- | freebsd/sbin/dhclient/options.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/freebsd/sbin/dhclient/options.c b/freebsd/sbin/dhclient/options.c index 09aa4d8f..17643e76 100644 --- a/freebsd/sbin/dhclient/options.c +++ b/freebsd/sbin/dhclient/options.c @@ -55,6 +55,10 @@ void parse_options(struct packet *); void parse_option_buffer(struct packet *, unsigned char *, int); int store_options(unsigned char *, int, struct tree_cache **, unsigned char *, int, int, int, int); +void expand_domain_search(struct packet *packet); +int find_search_domain_name_len(struct option_data *option, int *offset); +void expand_search_domain_name(struct option_data *option, int *offset, + unsigned char **domain_search); /* @@ -94,6 +98,11 @@ parse_options(struct packet *packet) (unsigned char *)packet->raw->sname, sizeof(packet->raw->sname)); } + + /* Expand DHCP Domain Search option. */ + if (packet->options_valid) { + expand_domain_search(packet); + } } /* @@ -194,6 +203,171 @@ parse_option_buffer(struct packet *packet, } /* + * Expand DHCP Domain Search option. The value of this option is + * encoded like DNS' list of labels. See: + * RFC 3397 + * RFC 1035 + */ +void +expand_domain_search(struct packet *packet) +{ + int offset, expanded_len, next_domain_len; + struct option_data *option; + unsigned char *domain_search, *cursor; + + if (packet->options[DHO_DOMAIN_SEARCH].data == NULL) + return; + + option = &packet->options[DHO_DOMAIN_SEARCH]; + + /* Compute final expanded length. */ + expanded_len = 0; + offset = 0; + while (offset < option->len) { + next_domain_len = find_search_domain_name_len(option, &offset); + if (next_domain_len < 0) + /* The Domain Search option value is invalid. */ + return; + + /* We add 1 for the space between domain names. */ + expanded_len += next_domain_len + 1; + } + if (expanded_len > 0) + /* Remove 1 for the superfluous trailing space. */ + --expanded_len; + + domain_search = malloc(expanded_len + 1); + if (domain_search == NULL) + error("Can't allocate storage for expanded domain-search\n"); + + offset = 0; + cursor = domain_search; + while (offset < option->len) { + expand_search_domain_name(option, &offset, &cursor); + cursor[0] = ' '; + cursor++; + } + domain_search[expanded_len] = '\0'; + + free(option->data); + option->len = expanded_len; + option->data = domain_search; +} + +int +find_search_domain_name_len(struct option_data *option, int *offset) +{ + int domain_name_len, i, label_len, pointer, pointed_len; + + domain_name_len = 0; + + i = *offset; + while (i < option->len) { + label_len = option->data[i]; + if (label_len == 0) { + /* + * A zero-length label marks the end of this + * domain name. + */ + *offset = i + 1; + return (domain_name_len); + } else if (label_len & 0xC0) { + /* This is a pointer to another list of labels. */ + if (i + 1 >= option->len) { + /* The pointer is truncated. */ + warning("Truncated pointer in DHCP Domain " + "Search option."); + return (-1); + } + + pointer = ((label_len & ~(0xC0)) << 8) + + option->data[i + 1]; + if (pointer >= *offset) { + /* + * The pointer must indicates a prior + * occurance. + */ + warning("Invalid forward pointer in DHCP " + "Domain Search option compression."); + return (-1); + } + + pointed_len = find_search_domain_name_len(option, + &pointer); + domain_name_len += pointed_len; + + *offset = i + 2; + return (domain_name_len); + } + + if (i + label_len >= option->len) { + warning("Truncated label in DHCP Domain Search " + "option."); + return (-1); + } + + /* + * Update the domain name length with the length of the + * current label, plus a trailing dot ('.'). + */ + domain_name_len += label_len + 1; + + /* Move cursor. */ + i += label_len + 1; + } + + warning("Truncated DHCP Domain Search option."); + + return (-1); +} + +void +expand_search_domain_name(struct option_data *option, int *offset, + unsigned char **domain_search) +{ + int i, label_len, pointer; + unsigned char *cursor; + + /* + * This is the same loop than the function above + * (find_search_domain_name_len). Therefore, we remove checks, + * they're already done. Here, we just make the copy. + */ + i = *offset; + cursor = *domain_search; + while (i < option->len) { + label_len = option->data[i]; + if (label_len == 0) { + /* + * A zero-length label marks the end of this + * domain name. + */ + *offset = i + 1; + *domain_search = cursor; + return; + } else if (label_len & 0xC0) { + /* This is a pointer to another list of labels. */ + pointer = ((label_len & ~(0xC0)) << 8) + + option->data[i + 1]; + + expand_search_domain_name(option, &pointer, &cursor); + + *offset = i + 2; + *domain_search = cursor; + return; + } + + /* Copy the label found. */ + memcpy(cursor, option->data + i + 1, label_len); + cursor[label_len] = '.'; + + /* Move cursor. */ + i += label_len + 1; + cursor += label_len + 1; + } +} + +/* * cons options into a big buffer, and then split them out into the * three separate buffers if needed. This allows us to cons up a set of * vendor options using the same routine. |