fill_envp now iterates over the packet only once instead of a few hundred times using the new option scanner.
Signed-off-by: Martin Lewis <[email protected]> --- networking/udhcp/dhcpc.c | 201 ++++++++++++++++++++--------------------------- 1 file changed, 87 insertions(+), 114 deletions(-) diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index 102178a4f..2669428e1 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -386,59 +386,81 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ return ret; } +static void putenvp(llist_t **envp, char *new_opt) +{ + putenv(new_opt); + llist_add_to(envp, new_opt); +} + +static int is_unknown_opt(uint8_t code, const struct dhcp_optflag **dh, const char **opt_name) +{ + *opt_name = ""; + + /* Find the option: + * dhcp_optflags is sorted so we stop searching when dh->code >= code, which is faster + * than iterating over the entire array. + * Options which don't have a match in dhcp_option_strings[], e.g DHCP_REQUESTED_IP, + * are located after the sorted array, so these entries will never be reached + * and they'll count as unknown options. + */ + for (*dh = dhcp_optflags; (*dh)->code && (*dh)->code < code; (*dh)++); + + if ((*dh)->code == code) + *opt_name = nth_string(dhcp_option_strings, (*dh - dhcp_optflags)); + + return (*dh)->code > code; +} + /* put all the parameters into the environment */ -static char **fill_envp(struct dhcp_packet *packet) +static llist_t *fill_envp(struct dhcp_packet *packet) { - int envc; - int i; - char **envp, **curr; - const char *opt_name; - uint8_t *temp; - uint8_t overload = 0; - -#define BITMAP unsigned -#define BBITS (sizeof(BITMAP) * 8) -#define BMASK(i) (1 << (i & (sizeof(BITMAP) * 8 - 1))) -#define FOUND_OPTS(i) (found_opts[(unsigned)i / BBITS]) - BITMAP found_opts[256 / BBITS]; - - memset(found_opts, 0, sizeof(found_opts)); - - /* We need 7 elements for: - * "interface=IFACE" - * "ip=N.N.N.N" from packet->yiaddr - * "giaddr=IP" from packet->gateway_nip (unless 0) - * "siaddr=IP" from packet->siaddr_nip (unless 0) - * "boot_file=FILE" from packet->file (unless overloaded) - * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded) - * terminating NULL - */ - envc = 7; - /* +1 element for each option, +2 for subnet option: */ - if (packet) { - /* note: do not search for "pad" (0) and "end" (255) options */ -//TODO: change logic to scan packet _once_ - for (i = 1; i < 255; i++) { - temp = udhcp_get_option(packet, i); - if (temp) { - if (i == DHCP_OPTION_OVERLOAD) - overload |= *temp; - else if (i == DHCP_SUBNET) - envc++; /* for $mask */ - envc++; - /*if (i != DHCP_MESSAGE_TYPE)*/ - FOUND_OPTS(i) |= BMASK(i); - } - } - } - curr = envp = xzalloc(sizeof(envp[0]) * envc); + char *new_opt; + uint8_t *optptr; + const struct dhcp_optflag *dh; + struct dhcp_scan_state scan_state; + const char *opt_name = ""; + llist_t *envp = NULL; - *curr = xasprintf("interface=%s", client_data.interface); - putenv(*curr++); + new_opt = xasprintf("interface=%s", client_data.interface); + putenvp(&envp, new_opt); if (!packet) return envp; + 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. + */ + while ((optptr = udhcp_scan_options(packet, &scan_state)) != NULL) { + uint8_t code = optptr[OPT_CODE]; + uint8_t len = optptr[OPT_LEN]; + uint8_t *data = optptr + OPT_DATA; + + if (is_unknown_opt(code, &dh, &opt_name)) { + 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'; + putenvp(&envp, new_opt); + } else { + new_opt = xmalloc_optname_optval(data, dh, opt_name); + putenvp(&envp, new_opt); + + if (code == DHCP_SUBNET && len == 4) { + uint32_t subnet; + move_from_unaligned32(subnet, data); + new_opt = xasprintf("mask=%u", mton(subnet)); + putenvp(&envp, new_opt); + } + } + } + /* Export BOOTP fields. Fields we don't (yet?) export: * uint8_t op; // always BOOTREPLY * uint8_t htype; // hardware address type. 1 = 10mb ethernet @@ -452,77 +474,31 @@ static char **fill_envp(struct dhcp_packet *packet) * uint8_t chaddr[16]; // link-layer client hardware address (MAC) */ /* Most important one: yiaddr as $ip */ - *curr = xmalloc(sizeof("ip=255.255.255.255")); - sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr); - putenv(*curr++); + new_opt = xmalloc(sizeof("ip=255.255.255.255")); + sprint_nip(new_opt, "ip=", (uint8_t *) &packet->yiaddr); + putenvp(&envp, new_opt); + if (packet->siaddr_nip) { /* IP address of next server to use in bootstrap */ - *curr = xmalloc(sizeof("siaddr=255.255.255.255")); - sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip); - putenv(*curr++); + new_opt = xmalloc(sizeof("siaddr=255.255.255.255")); + sprint_nip(new_opt, "siaddr=", (uint8_t *) &packet->siaddr_nip); + putenvp(&envp, new_opt); } if (packet->gateway_nip) { /* IP address of DHCP relay agent */ - *curr = xmalloc(sizeof("giaddr=255.255.255.255")); - sprint_nip(*curr, "giaddr=", (uint8_t *) &packet->gateway_nip); - putenv(*curr++); + new_opt = xmalloc(sizeof("giaddr=255.255.255.255")); + sprint_nip(new_opt, "giaddr=", (uint8_t *) &packet->gateway_nip); + putenvp(&envp, new_opt); } - if (!(overload & FILE_FIELD) && packet->file[0]) { + if (!(scan_state.overload & FILE_FIELD) && packet->file[0]) { /* watch out for invalid packets */ - *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file); - putenv(*curr++); + new_opt = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file); + putenvp(&envp, new_opt); } - if (!(overload & SNAME_FIELD) && packet->sname[0]) { + if (!(scan_state.overload & SNAME_FIELD) && packet->sname[0]) { /* watch out for invalid packets */ - *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname); - putenv(*curr++); - } - - /* Export known DHCP options */ - opt_name = dhcp_option_strings; - i = 0; - while (*opt_name) { - uint8_t code = dhcp_optflags[i].code; - BITMAP *found_ptr = &FOUND_OPTS(code); - BITMAP found_mask = BMASK(code); - if (!(*found_ptr & found_mask)) - goto next; - *found_ptr &= ~found_mask; /* leave only unknown options */ - temp = udhcp_get_option(packet, code); - *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name); - putenv(*curr++); - if (code == DHCP_SUBNET && temp[-OPT_DATA + OPT_LEN] == 4) { - /* Subnet option: make things like "$ip/$mask" possible */ - uint32_t subnet; - move_from_unaligned32(subnet, temp); - *curr = xasprintf("mask=%u", mton(subnet)); - putenv(*curr++); - } - next: - opt_name += strlen(opt_name) + 1; - i++; - } - /* Export unknown options */ - for (i = 0; i < 256;) { - BITMAP bitmap = FOUND_OPTS(i); - if (!bitmap) { - i += BBITS; - continue; - } - if (bitmap & BMASK(i)) { - unsigned len, ofs; - - temp = udhcp_get_option(packet, i); - /* udhcp_get_option returns ptr to data portion, - * need to go back to get len - */ - len = temp[-OPT_DATA + OPT_LEN]; - *curr = xmalloc(sizeof("optNNN=") + 1 + len*2); - ofs = sprintf(*curr, "opt%u=", i); - *bin2hex(*curr + ofs, (void*) temp, len) = '\0'; - putenv(*curr++); - } - i++; + new_opt = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname); + putenvp(&envp, new_opt); } return envp; @@ -531,7 +507,7 @@ static char **fill_envp(struct dhcp_packet *packet) /* Call a script with a par file and env vars */ static void udhcp_run_script(struct dhcp_packet *packet, const char *name) { - char **envp, **curr; + llist_t *envp; char *argv[3]; envp = fill_envp(packet); @@ -543,11 +519,8 @@ static void udhcp_run_script(struct dhcp_packet *packet, const char *name) argv[2] = NULL; spawn_and_wait(argv); - for (curr = envp; *curr; curr++) { - log2(" %s", *curr); - bb_unsetenv_and_free(*curr); - } - free(envp); + /* Free all allocated environment variables */ + llist_free(envp, (void (*)(void *))bb_unsetenv_and_free); } -- 2.11.0 _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
