diff options
| -rw-r--r-- | networking/udhcp/dhcpc.c | 138 | ||||
| -rw-r--r-- | networking/udhcp/dhcpc.h | 1 |
2 files changed, 104 insertions, 35 deletions
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index 50dfead63..e13eb3f9f 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -115,6 +115,13 @@ enum { /*** Script execution code ***/ +struct dhcp_optitem { + unsigned len; + uint8_t code; + uint8_t malloced; + uint8_t *data; + char *env; +}; /* get a rough idea of how long an option will be (rounding up...) */ static const uint8_t len_of_option_as_string[] ALIGN1 = { @@ -186,15 +193,15 @@ static int good_hostname(const char *name) #endif /* Create "opt_name=opt_value" string */ -static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name) +static NOINLINE char *xmalloc_optname_optval(const struct dhcp_optitem *opt_item, const struct dhcp_optflag *optflag, const char *opt_name) { unsigned upper_length; int len, type, optlen; char *dest, *ret; + uint8_t *option; - /* option points to OPT_DATA, need to go back to get OPT_LEN */ - len = option[-OPT_DATA + OPT_LEN]; - + option = opt_item->data; + len = opt_item->len; type = optflag->flags & OPTION_TYPE_MASK; optlen = dhcp_option_lengths[type]; upper_length = len_of_option_as_string[type] @@ -386,11 +393,70 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ return ret; } -static void putenvp(llist_t **envp, char *new_opt) +static void optitem_unset_env_and_free(void *item) { - putenv(new_opt); + struct dhcp_optitem *opt_item = item; + bb_unsetenv_and_free(opt_item->env); + if (opt_item->malloced) + free(opt_item->data); + free(opt_item); +} + +/* Used by static options (interface, siaddr, etc) */ +static void putenvp(char *new_opt) +{ + struct dhcp_optitem *opt_item; + + opt_item = xzalloc(sizeof(*opt_item)); + /* opt_item->code = 0, so it won't appear in concat_option's lookup */ + /* opt_item->malloced = 0 */ + /* opt_item->data = NULL */ + opt_item->env = new_opt; + llist_add_to(&client_data.envp, opt_item); log2(" %s", new_opt); - llist_add_to(envp, new_opt); + putenv(new_opt); +} + +/* Support RFC3396 Long Encoded Options */ +static struct dhcp_optitem *concat_option(uint8_t *data, uint8_t len, uint8_t code) +{ + llist_t *item; + struct dhcp_optitem *opt_item; + + /* Check if an option with the code already exists. + * A possible optimization is to create a bitmap of all existing options in the packet, + * and iterate over the option list only if they exist. + * This will result in bigger code, and because dhcp packets don't have too many options it + * shouldn't have a big impact on performance. + */ + for (item = client_data.envp; item != NULL; item = item->link) { + opt_item = (struct dhcp_optitem *)item->data; + if (opt_item->code == code) { + /* This option was seen already, concatenate */ + uint8_t *new_data; + + new_data = xmalloc(len + opt_item->len); + memcpy( + mempcpy(new_data, opt_item->data, opt_item->len), + data, len + ); + opt_item->len += len; + if (opt_item->malloced) + free(opt_item->data); + opt_item->malloced = 1; + opt_item->data = new_data; + return opt_item; + } + } + + /* This is a new option, add a new dhcp_optitem to the list */ + opt_item = xzalloc(sizeof(*opt_item)); + opt_item->code = code; + /* opt_item->malloced = 0 */ + opt_item->data = data; + opt_item->len = len; + llist_add_to(&client_data.envp, opt_item); + return opt_item; } static const char* get_optname(uint8_t code, const struct dhcp_optflag **dh) @@ -403,7 +469,7 @@ static const char* get_optname(uint8_t code, const struct dhcp_optflag **dh) * and they'll count as unknown options. */ for (*dh = dhcp_optflags; (*dh)->code && (*dh)->code < code; (*dh)++) - continue; + continue; if ((*dh)->code == code) return nth_string(dhcp_option_strings, (*dh - dhcp_optflags)); @@ -412,50 +478,54 @@ static const char* get_optname(uint8_t code, const struct dhcp_optflag **dh) } /* put all the parameters into the environment */ -static llist_t *fill_envp(struct dhcp_packet *packet) +static void fill_envp(struct dhcp_packet *packet) { uint8_t *optptr; struct dhcp_scan_state scan_state; char *new_opt; - llist_t *envp = NULL; - putenvp(&envp, xasprintf("interface=%s", client_data.interface)); + putenvp(xasprintf("interface=%s", client_data.interface)); if (!packet) - return envp; + return; init_scan_state(packet, &scan_state); /* Iterate over the packet options. * Handle each option based on whether it's an unknown / known option. - * There may be (although unlikely) duplicate options. For now, only the last - * appearing option will be stored in the environment, and all duplicates - * are freed properly. - * Long options may be implemented in the future (see RFC 3396) if needed. + * Long options are supported in compliance with RFC 3396. */ while ((optptr = udhcp_scan_options(packet, &scan_state)) != NULL) { const struct dhcp_optflag *dh; const char *opt_name; + struct dhcp_optitem *opt_item; uint8_t code = optptr[OPT_CODE]; uint8_t len = optptr[OPT_LEN]; uint8_t *data = optptr + OPT_DATA; + opt_item = concat_option(data, len, code); opt_name = get_optname(code, &dh); if (opt_name) { - new_opt = xmalloc_optname_optval(data, dh, opt_name); - if (code == DHCP_SUBNET && len == 4) { + new_opt = xmalloc_optname_optval(opt_item, dh, opt_name); + if (opt_item->code == DHCP_SUBNET && opt_item->len == 4) { + /* Generate extra envvar for DHCP_SUBNET, $mask */ uint32_t subnet; - putenvp(&envp, new_opt); - move_from_unaligned32(subnet, data); - new_opt = xasprintf("mask=%u", mton(subnet)); + move_from_unaligned32(subnet, opt_item->data); + putenvp(xasprintf("mask=%u", mton(subnet))); } } else { unsigned ofs; - new_opt = xmalloc(sizeof("optNNN=") + 1 + len*2); - ofs = sprintf(new_opt, "opt%u=", code); - bin2hex(new_opt + ofs, (char *)data, len)[0] = '\0'; + new_opt = xmalloc(sizeof("optNNN=") + 1 + opt_item->len*2); + ofs = sprintf(new_opt, "opt%u=", opt_item->code); + bin2hex(new_opt + ofs, (char *)opt_item->data, opt_item->len)[0] = '\0'; } - putenvp(&envp, new_opt); + log2(" %s", new_opt); + putenv(new_opt); + /* putenv will replace the existing environment variable in case of a duplicate. + * Free the previous occurrence (NULL if it's the first one). + */ + free(opt_item->env); + opt_item->env = new_opt; } /* Export BOOTP fields. Fields we don't (yet?) export: @@ -473,41 +543,38 @@ static llist_t *fill_envp(struct dhcp_packet *packet) /* Most important one: yiaddr as $ip */ new_opt = xmalloc(sizeof("ip=255.255.255.255")); sprint_nip(new_opt, "ip=", (uint8_t *) &packet->yiaddr); - putenvp(&envp, new_opt); + putenvp(new_opt); if (packet->siaddr_nip) { /* IP address of next server to use in bootstrap */ new_opt = xmalloc(sizeof("siaddr=255.255.255.255")); sprint_nip(new_opt, "siaddr=", (uint8_t *) &packet->siaddr_nip); - putenvp(&envp, new_opt); + putenvp(new_opt); } if (packet->gateway_nip) { /* IP address of DHCP relay agent */ new_opt = xmalloc(sizeof("giaddr=255.255.255.255")); sprint_nip(new_opt, "giaddr=", (uint8_t *) &packet->gateway_nip); - putenvp(&envp, new_opt); + putenvp(new_opt); } if (!(scan_state.overload & FILE_FIELD) && packet->file[0]) { /* watch out for invalid packets */ new_opt = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file); - putenvp(&envp, new_opt); + putenvp(new_opt); } if (!(scan_state.overload & SNAME_FIELD) && packet->sname[0]) { /* watch out for invalid packets */ new_opt = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname); - putenvp(&envp, new_opt); + putenvp(new_opt); } - - return envp; } /* Call a script with a par file and env vars */ static void udhcp_run_script(struct dhcp_packet *packet, const char *name) { - llist_t *envp; char *argv[3]; - envp = fill_envp(packet); + fill_envp(packet); /* call script */ log1("executing %s %s", client_data.script, name); @@ -517,7 +584,8 @@ static void udhcp_run_script(struct dhcp_packet *packet, const char *name) spawn_and_wait(argv); /* Free all allocated environment variables */ - llist_free(envp, (void (*)(void *))bb_unsetenv_and_free); + llist_free(client_data.envp, optitem_unset_env_and_free); + client_data.envp = NULL; } diff --git a/networking/udhcp/dhcpc.h b/networking/udhcp/dhcpc.h index b407a6cdb..7ad01ea8f 100644 --- a/networking/udhcp/dhcpc.h +++ b/networking/udhcp/dhcpc.h @@ -21,6 +21,7 @@ struct client_data_t { uint8_t *vendorclass; /* Optional vendor class-id to use */ uint8_t *hostname; /* Optional hostname to use */ uint8_t *fqdn; /* Optional fully qualified domain name to use */ + llist_t *envp; /* list of DHCP options used for env vars */ unsigned first_secs; unsigned last_secs; |