/src/frr/lib/command_match.c

Source
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Input matching routines for CLI backend.
 *
 * --
 * Copyright (C) 2016 Cumulus Networks, Inc.
 */

#include <zebra.h>

#include "command_match.h"
#include "memory.h"
#include "asn.h"

DEFINE_MTYPE_STATIC(LIB, CMD_MATCHSTACK, "Command Match Stack");

#ifdef TRACE_MATCHER
#define TM 1
#else
#define TM 0
#endif

#define trace_matcher(...)                                                     \
  do {                                                                   \
    if (TM)                                                        \
      fprintf(stderr, __VA_ARGS__);                          \
  } while (0);

/* matcher helper prototypes */
static int add_nexthops(struct list *, struct graph_node *,
      struct graph_node **, size_t, bool);

static enum matcher_rv command_match_r(struct graph_node *, vector,
               unsigned int, struct graph_node **,
               struct list **);

static int score_precedence(enum cmd_token_type);

static enum match_type min_match_level(enum cmd_token_type);

static void del_arglist(struct list *);

static struct cmd_token *disambiguate_tokens(struct cmd_token *,
               struct cmd_token *, char *);

static struct list *disambiguate(struct list *, struct list *, vector,
         unsigned int);

int compare_completions(const void *, const void *);

/* token matcher prototypes */
static enum match_type match_token(struct cmd_token *, char *);

static enum match_type match_ipv4(const char *);

static enum match_type match_ipv4_prefix(const char *);

static enum match_type match_ipv6_prefix(const char *, bool);

static enum match_type match_range(struct cmd_token *, const char *);

static enum match_type match_word(struct cmd_token *, const char *);

static enum match_type match_variable(struct cmd_token *, const char *);

static enum match_type match_mac(const char *, bool);

static bool is_neg(vector vline, size_t idx)
{
  if (idx >= vector_active(vline) || !vector_slot(vline, idx))
    return false;
  return !strcmp(vector_slot(vline, idx), "no");
}

enum matcher_rv command_match(struct graph *cmdgraph, vector vline,
            struct list **argv, const struct cmd_element **el)
{
  struct graph_node *stack[CMD_ARGC_MAX];
  enum matcher_rv status;
  *argv = NULL;

  // prepend a dummy token to match that pesky start node
  vector vvline = vector_init(vline->alloced + 1);
  vector_set_index(vvline, 0, XSTRDUP(MTYPE_TMP, "dummy"));
  memcpy(vvline->index + 1, vline->index,
         sizeof(void *) * vline->alloced);
  vvline->active = vline->active + 1;

  struct graph_node *start = vector_slot(cmdgraph->nodes, 0);
  status = command_match_r(start, vvline, 0, stack, argv);
  if (status == MATCHER_OK) { // successful match
    struct listnode *head = listhead(*argv);
    struct listnode *tail = listtail(*argv);

    assert(head);
    assert(tail);

    // delete dummy start node
    cmd_token_del((struct cmd_token *)head->data);
    list_delete_node(*argv, head);

    // get cmd_element out of list tail
    *el = listgetdata(tail);
    list_delete_node(*argv, tail);

    // now argv is an ordered list of cmd_token matching the user
    // input, with each cmd_token->arg holding the corresponding
    // input
    assert(*el);
  } else if (*argv) {
    del_arglist(*argv);
    *argv = NULL;
  }

  if (!*el) {
    trace_matcher("No match\n");
  } else {
    trace_matcher("Matched command\n->string %s\n->desc %s\n",
            (*el)->string, (*el)->doc);
  }

  // free the leader token we alloc'd
  XFREE(MTYPE_TMP, vector_slot(vvline, 0));
  // free vector
  vector_free(vvline);

  return status;
}

/**
 * Builds an argument list given a DFA and a matching input line.
 *
 * First the function determines if the node it is passed matches the first
 * token of input. If it does not, it returns NULL (MATCHER_NO_MATCH). If it
 * does match, then it saves the input token as the head of an argument list.
 *
 * The next step is to see if there is further input in the input line. If
 * there is not, the current node's children are searched to see if any of them
 * are leaves (type END_TKN). If this is the case, then the bottom of the
 * recursion stack has been reached, the leaf is pushed onto the argument list,
 * the current node is pushed, and the resulting argument list is
 * returned (MATCHER_OK). If it is not the case, NULL is returned, indicating
 * that there is no match for the input along this path (MATCHER_INCOMPLETE).
 *
 * If there is further input, then the function recurses on each of the current
 * node's children, passing them the input line minus the token that was just
 * matched. For each child, the return value of the recursive call is
 * inspected. If it is null, then there is no match for the input along the
 * subgraph headed by that child. If it is not null, then there is at least one
 * input match in that subgraph (more on this in a moment).
 *
 * If a recursive call on a child returns a non-null value, then it has matched
 * the input given it on the subgraph that starts with that child. However, due
 * to the flexibility of the grammar, it is sometimes the case that two or more
 * child graphs match the same input (two or more of the recursive calls have
 * non-NULL return values). This is not a valid state, since only one true
 * match is possible. In order to resolve this conflict, the function keeps a
 * reference to the child node that most specifically matches the input. This
 * is done by assigning each node type a precedence. If a child is found to
 * match the remaining input, then the precedence values of the current
 * best-matching child and this new match are compared. The node with higher
 * precedence is kept, and the other match is discarded. Due to the recursive
 * nature of this function, it is only necessary to compare the precedence of
 * immediate children, since all subsequent children will already have been
 * disambiguated in this way.
 *
 * In the event that two children are found to match with the same precedence,
 * then the input is ambiguous for the passed cmd_element and NULL is returned.
 *
 * @param[in] start the start node.
 * @param[in] vline the vectorized input line.
 * @param[in] n the index of the first input token.
 * @return A linked list of n elements. The first n-1 elements are pointers to
 * struct cmd_token and represent the sequence of tokens matched by the input.
 * The ->arg field of each token points to a copy of the input matched on it.
 * The final nth element is a pointer to struct cmd_element, which is the
 * command that was matched.
 *
 * If no match was found, the return value is NULL.
 */
static enum matcher_rv command_match_r(struct graph_node *start, vector vline,
               unsigned int n,
               struct graph_node **stack,
               struct list **currbest)
{
  assert(n < vector_active(vline));

  enum matcher_rv status = MATCHER_NO_MATCH;

  // get the minimum match level that can count as a full match
  struct cmd_token *copy, *token = start->data;
  enum match_type minmatch = min_match_level(token->type);

  /* check history/stack of tokens
   * this disallows matching the same one more than once if there is a
   * circle in the graph (used for keyword arguments) */
  if (n == CMD_ARGC_MAX)
    return MATCHER_NO_MATCH;
  if (!token->allowrepeat)
    for (size_t s = 0; s < n; s++)
      if (stack[s] == start)
        return MATCHER_NO_MATCH;

  // get the current operating input token
  char *input_token = vector_slot(vline, n);

#ifdef TRACE_MATCHER
  fprintf(stdout, "\"%-20s\" matches \"%-30s\" ? ", input_token,
    token->text);
  enum match_type mt = match_token(token, input_token);
  fprintf(stdout, "type: %d ", token->type);
  fprintf(stdout, "min: %d - ", minmatch);
  switch (mt) {
  case trivial_match:
    fprintf(stdout, "trivial_match ");
    break;
  case no_match:
    fprintf(stdout, "no_match ");
    break;
  case partly_match:
    fprintf(stdout, "partly_match ");
    break;
  case exact_match:
    fprintf(stdout, "exact_match ");
    break;
  }
  if (mt >= minmatch)
    fprintf(stdout, " MATCH");
  fprintf(stdout, "\n");
#endif

  // if we don't match this node, die
  if (match_token(token, input_token) < minmatch)
    return MATCHER_NO_MATCH;

  stack[n] = start;

  // pointers for iterating linklist
  struct listnode *ln;
  struct graph_node *gn;

  // get all possible nexthops
  struct list *next = list_new();
  add_nexthops(next, start, NULL, 0, is_neg(vline, 1));

  // determine the best match
  for (ALL_LIST_ELEMENTS_RO(next, ln, gn)) {
    // if we've matched all input we're looking for END_TKN
    if (n + 1 == vector_active(vline)) {
      struct cmd_token *tok = gn->data;
      if (tok->type == END_TKN) {
        // if more than one END_TKN in the follow set
        if (*currbest) {
          status = MATCHER_AMBIGUOUS;
          break;
        } else {
          status = MATCHER_OK;
        }
        *currbest = list_new();
        // node should have one child node with the
        // element
        struct graph_node *leaf =
          vector_slot(gn->to, 0);
        // last node in the list will hold the
        // cmd_element; this is important because
        // list_delete() expects that all nodes have
        // the same data type, so when deleting this
        // list the last node must be manually deleted
        struct cmd_element *el = leaf->data;
        listnode_add(*currbest, el);
        (*currbest)->del =
          (void (*)(void *)) & cmd_token_del;
        // do not break immediately; continue walking
        // through the follow set to ensure that there
        // is exactly one END_TKN
      }
      continue;
    }

    // else recurse on candidate child node
    struct list *result = NULL;
    enum matcher_rv rstat =
      command_match_r(gn, vline, n + 1, stack, &result);

    // save the best match
    if (result && *currbest) {
      // pick the best of two matches
      struct list *newbest =
        disambiguate(*currbest, result, vline, n + 1);

      // current best and result are ambiguous
      if (!newbest)
        status = MATCHER_AMBIGUOUS;
      // current best is still the best, but ambiguous
      else if (newbest == *currbest
         && status == MATCHER_AMBIGUOUS)
        status = MATCHER_AMBIGUOUS;
      // result is better, but also ambiguous
      else if (newbest == result
         && rstat == MATCHER_AMBIGUOUS)
        status = MATCHER_AMBIGUOUS;
      // one or the other is superior and not ambiguous
      else
        status = MATCHER_OK;

      // delete the unnecessary result
      struct list *todelete =
        ((newbest && newbest == result) ? *currbest
                : result);
      del_arglist(todelete);

      *currbest = newbest ? newbest : *currbest;
    } else if (result) {
      status = rstat;
      *currbest = result;
    } else if (!*currbest) {
      status = MAX(rstat, status);
    }
  }
  if (*currbest) {
    // copy token, set arg and prepend to currbest
    token = start->data;
    copy = cmd_token_dup(token);
    copy->arg = XSTRDUP(MTYPE_CMD_ARG, input_token);
    listnode_add_before(*currbest, (*currbest)->head, copy);
  } else if (n + 1 == vector_active(vline) && status == MATCHER_NO_MATCH)
    status = MATCHER_INCOMPLETE;

  // cleanup
  list_delete(&next);

  return status;
}

static void stack_del(void *val)
{
  XFREE(MTYPE_CMD_MATCHSTACK, val);
}

enum matcher_rv command_complete(struct graph *graph, vector vline,
         struct list **completions)
{
  // pointer to next input token to match
  char *input_token;
  bool neg = is_neg(vline, 0);

  struct list *
    current =
           list_new(), // current nodes to match input token against
    *next = list_new(); // possible next hops after current input
            // token
  current->del = next->del = stack_del;

  // pointers used for iterating lists
  struct graph_node **gstack, **newstack;
  struct listnode *node;

  // add all children of start node to list
  struct graph_node *start = vector_slot(graph->nodes, 0);
  add_nexthops(next, start, &start, 0, neg);

  unsigned int idx;
  for (idx = 0; idx < vector_active(vline) && next->count > 0; idx++) {
    list_delete(&current);
    current = next;
    next = list_new();
    next->del = stack_del;

    input_token = vector_slot(vline, idx);

    int exact_match_exists = 0;
    for (ALL_LIST_ELEMENTS_RO(current, node, gstack))
      if (!exact_match_exists)
        exact_match_exists =
          (match_token(gstack[0]->data,
                 input_token)
           == exact_match);
      else
        break;

    for (ALL_LIST_ELEMENTS_RO(current, node, gstack)) {
      struct cmd_token *token = gstack[0]->data;

      if (token->attr & CMD_ATTR_HIDDEN)
        continue;

      enum match_type minmatch = min_match_level(token->type);
      trace_matcher("\"%s\" matches \"%s\" (%d) ? ",
              input_token, token->text, token->type);

      unsigned int last_token =
        (vector_active(vline) - 1 == idx);
      enum match_type matchtype =
        match_token(token, input_token);
      switch (matchtype) {
      // occurs when last token is whitespace
      case trivial_match:
        trace_matcher("trivial_match\n");
        assert(last_token);
        newstack = XMALLOC(MTYPE_CMD_MATCHSTACK,
               sizeof(struct graph_node *));
        /* we're not recursing here, just the first
         * element is OK */
        newstack[0] = gstack[0];
        listnode_add(next, newstack);
        break;
      case partly_match:
        trace_matcher("trivial_match\n");
        if (exact_match_exists && !last_token)
          break;
      /* fallthru */
      case exact_match:
        trace_matcher("exact_match\n");
        if (last_token) {
          newstack = XMALLOC(
            MTYPE_CMD_MATCHSTACK,
            sizeof(struct graph_node *));
          /* same as above, not recursing on this
           */
          newstack[0] = gstack[0];
          listnode_add(next, newstack);
        } else if (matchtype >= minmatch)
          add_nexthops(next, gstack[0], gstack,
                 idx + 1, neg);
        break;
      case no_match:
        trace_matcher("no_match\n");
        break;
      }
    }
  }

  /* Variable summary
   * -----------------------------------------------------------------
   * token    = last input token processed
   * idx      = index in `command` of last token processed
   * current  = set of all transitions from the previous input token
   * next     = set of all nodes reachable from all nodes in `matched`
   */

  enum matcher_rv mrv = idx == vector_active(vline) && next->count
              ? MATCHER_OK
              : MATCHER_NO_MATCH;

  *completions = NULL;
  if (!MATCHER_ERROR(mrv)) {
    // extract cmd_token into list
    *completions = list_new();
    for (ALL_LIST_ELEMENTS_RO(next, node, gstack)) {
      listnode_add(*completions, gstack[0]->data);
    }
  }

  list_delete(&current);
  list_delete(&next);

  return mrv;
}

/**
 * Adds all children that are reachable by one parser hop to the given list.
 * special tokens except END_TKN are treated as transparent.
 *
 * @param[in] list to add the nexthops to
 * @param[in] node to start calculating nexthops from
 * @param[in] stack listing previously visited nodes, if non-NULL.
 * @param[in] stackpos how many valid entries are in stack
 * @return the number of children added to the list
 *
 * NB: non-null "stack" means that new stacks will be added to "list" as
 * output, instead of direct node pointers!
 */
static int add_nexthops(struct list *list, struct graph_node *node,
      struct graph_node **stack, size_t stackpos, bool neg)
{
  int added = 0;
  struct graph_node *child;
  struct graph_node **nextstack;
  for (unsigned int i = 0; i < vector_active(node->to); i++) {
    child = vector_slot(node->to, i);
    size_t j;
    struct cmd_token *token = child->data;
    if (!token->allowrepeat && stack) {
      for (j = 0; j < stackpos; j++)
        if (child == stack[j])
          break;
      if (j != stackpos)
        continue;
    }

    if (token->type == NEG_ONLY_TKN && !neg)
      continue;

    if (token->type >= SPECIAL_TKN && token->type != END_TKN) {
      added +=
        add_nexthops(list, child, stack, stackpos, neg);
    } else {
      if (stack) {
        nextstack = XMALLOC(
          MTYPE_CMD_MATCHSTACK,
          (stackpos + 1)
            * sizeof(struct graph_node *));
        nextstack[0] = child;
        memcpy(nextstack + 1, stack,
               stackpos * sizeof(struct graph_node *));

        listnode_add(list, nextstack);
      } else
        listnode_add(list, child);
      added++;
    }
  }

  return added;
}

/**
 * Determines the node types for which a partial match may count as a full
 * match. Enables command abbrevations.
 *
 * @param[in] type node type
 * @return minimum match level needed to for a token to fully match
 */
static enum match_type min_match_level(enum cmd_token_type type)
{
  switch (type) {
  // anything matches a start node, for the sake of recursion
  case START_TKN:
    return no_match;
  // allowing words to partly match enables command abbreviation
  case WORD_TKN:
    return partly_match;
  case RANGE_TKN:
  case IPV4_TKN:
  case IPV4_PREFIX_TKN:
  case IPV6_TKN:
  case IPV6_PREFIX_TKN:
  case MAC_TKN:
  case MAC_PREFIX_TKN:
  case FORK_TKN:
  case JOIN_TKN:
  case END_TKN:
  case NEG_ONLY_TKN:
  case VARIABLE_TKN:
  case ASNUM_TKN:
    return exact_match;
  }

  assert(!"Reached end of function we should never hit");
}

/**
 * Assigns precedence scores to node types.
 *
 * @param[in] type node type to score
 * @return precedence score
 */
static int score_precedence(enum cmd_token_type type)
{
  switch (type) {
  // some of these are mutually exclusive, so they share
  // the same precedence value
  case IPV4_TKN:
  case IPV4_PREFIX_TKN:
  case IPV6_TKN:
  case IPV6_PREFIX_TKN:
  case MAC_TKN:
  case MAC_PREFIX_TKN:
  case ASNUM_TKN:
  case RANGE_TKN:
    return 2;
  case WORD_TKN:
    return 3;
  case VARIABLE_TKN:
    return 4;
  case JOIN_TKN:
  case START_TKN:
  case END_TKN:
  case NEG_ONLY_TKN:
  case SPECIAL_TKN:
    return 10;
  }

  assert(!"Reached end of function we should never hit");
}

/**
 * Picks the better of two possible matches for a token.
 *
 * @param[in] first candidate node matching token
 * @param[in] second candidate node matching token
 * @param[in] token the token being matched
 * @return the best-matching node, or NULL if the two are entirely ambiguous
 */
static struct cmd_token *disambiguate_tokens(struct cmd_token *first,
               struct cmd_token *second,
               char *input_token)
{
  // if the types are different, simply go off of type precedence
  if (first->type != second->type) {
    int firstprec = score_precedence(first->type);
    int secndprec = score_precedence(second->type);
    if (firstprec != secndprec)
      return firstprec < secndprec ? first : second;
    else
      return NULL;
  }

  // if they're the same, return the more exact match
  enum match_type fmtype = match_token(first, input_token);
  enum match_type smtype = match_token(second, input_token);
  if (fmtype != smtype)
    return fmtype > smtype ? first : second;

  return NULL;
}

/**
 * Picks the better of two possible matches for an input line.
 *
 * @param[in] first candidate list of cmd_token matching vline
 * @param[in] second candidate list of cmd_token matching vline
 * @param[in] vline the input line being matched
 * @param[in] n index into vline to start comparing at
 * @return the best-matching list, or NULL if the two are entirely ambiguous
 */
static struct list *disambiguate(struct list *first, struct list *second,
         vector vline, unsigned int n)
{
  assert(first != NULL);
  assert(second != NULL);
  // doesn't make sense for these to be inequal length
  assert(first->count == second->count);
  assert(first->count == vector_active(vline) - n + 1);

  struct listnode *fnode = listhead_unchecked(first),
      *snode = listhead_unchecked(second);
  struct cmd_token *ftok = listgetdata(fnode), *stok = listgetdata(snode),
       *best = NULL;

  // compare each token, if one matches better use that one
  for (unsigned int i = n; i < vector_active(vline); i++) {
    char *token = vector_slot(vline, i);
    if ((best = disambiguate_tokens(ftok, stok, token)))
      return best == ftok ? first : second;
    fnode = listnextnode(fnode);
    snode = listnextnode(snode);
    ftok = listgetdata(fnode);
    stok = listgetdata(snode);
  }

  return NULL;
}

/*
 * Deletion function for arglist.
 *
 * Since list->del for arglists expects all listnode->data to hold cmd_token,
 * but arglists have cmd_element as the data for the tail, this function
 * manually deletes the tail before deleting the rest of the list as usual.
 *
 * The cmd_element at the end is *not* a copy. It is the one and only.
 *
 * @param list the arglist to delete
 */
static void del_arglist(struct list *list)
{
  // manually delete last node
  struct listnode *tail = listtail(list);
  tail->data = NULL;
  list_delete_node(list, tail);

  // delete the rest of the list as usual
  list_delete(&list);
}

/*---------- token level matching functions ----------*/

static enum match_type match_token(struct cmd_token *token, char *input_token)
{
  // nothing trivially matches everything
  if (!input_token)
    return trivial_match;

  switch (token->type) {
  case WORD_TKN:
    return match_word(token, input_token);
  case IPV4_TKN:
    return match_ipv4(input_token);
  case IPV4_PREFIX_TKN:
    return match_ipv4_prefix(input_token);
  case IPV6_TKN:
    return match_ipv6_prefix(input_token, false);
  case IPV6_PREFIX_TKN:
    return match_ipv6_prefix(input_token, true);
  case RANGE_TKN:
    return match_range(token, input_token);
  case VARIABLE_TKN:
    return match_variable(token, input_token);
  case MAC_TKN:
    return match_mac(input_token, false);
  case MAC_PREFIX_TKN:
    return match_mac(input_token, true);
  case ASNUM_TKN:
    return asn_str2asn_match(input_token);
  case END_TKN:
  case FORK_TKN:
  case JOIN_TKN:
  case START_TKN:
  case NEG_ONLY_TKN:
    return no_match;
  }

  assert(!"Reached end of function we should never hit");
}

#define IPV4_ADDR_STR   "0123456789."
#define IPV4_PREFIX_STR "0123456789./"

static enum match_type match_ipv4(const char *str)
{
  const char *sp;
  int dots = 0, nums = 0;
  char buf[4];

  for (;;) {
    memset(buf, 0, sizeof(buf));
    sp = str;
    while (*str != '\0') {
      if (*str == '.') {
        if (dots >= 3)
          return no_match;

        if (*(str + 1) == '.')
          return no_match;

        if (*(str + 1) == '\0')
          return partly_match;

        dots++;
        break;
      }
      if (!isdigit((unsigned char)*str))
        return no_match;

      str++;
    }

    if (str - sp > 3)
      return no_match;

    memcpy(buf, sp, str - sp);

    int v = atoi(buf);

    if (v > 255)
      return no_match;
    if (v > 0 && buf[0] == '0')
      return no_match;

    nums++;

    if (*str == '\0')
      break;

    str++;
  }

  if (nums < 4)
    return partly_match;

  return exact_match;
}

static enum match_type match_ipv4_prefix(const char *str)
{
  const char *sp;
  int dots = 0;
  char buf[4];

  for (;;) {
    memset(buf, 0, sizeof(buf));
    sp = str;
    while (*str != '\0' && *str != '/') {
      if (*str == '.') {
        if (dots == 3)
          return no_match;

        if (*(str + 1) == '.' || *(str + 1) == '/')
          return no_match;

        if (*(str + 1) == '\0')
          return partly_match;

        dots++;
        break;
      }

      if (!isdigit((unsigned char)*str))
        return no_match;

      str++;
    }

    if (str - sp > 3)
      return no_match;

    memcpy(buf, sp, str - sp);

    int v = atoi(buf);

    if (v > 255)
      return no_match;
    if (v > 0 && buf[0] == '0')
      return no_match;

    if (dots == 3) {
      if (*str == '/') {
        if (*(str + 1) == '\0')
          return partly_match;

        str++;
        break;
      } else if (*str == '\0')
        return partly_match;
    }

    if (*str == '\0')
      return partly_match;

    str++;
  }

  sp = str;
  while (*str != '\0') {
    if (!isdigit((unsigned char)*str))
      return no_match;

    str++;
  }

  if (atoi(sp) > IPV4_MAX_BITLEN)
    return no_match;

  return exact_match;
}

#define IPV6_ADDR_STR   "0123456789abcdefABCDEF:."
#define IPV6_PREFIX_STR "0123456789abcdefABCDEF:./"
#define STATE_START     1
#define STATE_COLON     2
#define STATE_DOUBLE    3
#define STATE_ADDR      4
#define STATE_DOT       5
#define STATE_SLASH     6
#define STATE_MASK      7

static enum match_type match_ipv6_prefix(const char *str, bool prefix)
{
  int state = STATE_START;
  int colons = 0, nums = 0, double_colon = 0;
  int mask;
  const char *sp = NULL, *start = str;
  char *endptr = NULL;

  if (str == NULL)
    return partly_match;

  if (strspn(str, prefix ? IPV6_PREFIX_STR : IPV6_ADDR_STR)
      != strlen(str))
    return no_match;

  while (*str != '\0' && state != STATE_MASK) {
    switch (state) {
    case STATE_START:
      if (*str == ':') {
        if (*(str + 1) != ':' && *(str + 1) != '\0')
          return no_match;
        colons--;
        state = STATE_COLON;
      } else {
        sp = str;
        state = STATE_ADDR;
      }

      continue;
    case STATE_COLON:
      colons++;
      if (*(str + 1) == '/')
        return no_match;
      else if (*(str + 1) == ':')
        state = STATE_DOUBLE;
      else {
        sp = str + 1;
        state = STATE_ADDR;
      }
      break;
    case STATE_DOUBLE:
      if (double_colon)
        return no_match;

      if (*(str + 1) == ':')
        return no_match;
      else {
        if (*(str + 1) != '\0' && *(str + 1) != '/')
          colons++;
        sp = str + 1;

        if (*(str + 1) == '/')
          state = STATE_SLASH;
        else
          state = STATE_ADDR;
      }

      double_colon++;
      nums += 1;
      break;
    case STATE_ADDR:
      if (*(str + 1) == ':' || *(str + 1) == '.'
          || *(str + 1) == '\0' || *(str + 1) == '/') {
        if (str - sp > 3)
          return no_match;

        for (; sp <= str; sp++)
          if (*sp == '/')
            return no_match;

        nums++;

        if (*(str + 1) == ':')
          state = STATE_COLON;
        else if (*(str + 1) == '.') {
          if (colons || double_colon)
            state = STATE_DOT;
          else
            return no_match;
        } else if (*(str + 1) == '/')
          state = STATE_SLASH;
      }
      break;
    case STATE_DOT:
      state = STATE_ADDR;
      break;
    case STATE_SLASH:
      if (*(str + 1) == '\0')
        return partly_match;

      state = STATE_MASK;
      break;
    default:
      break;
    }

    if (nums > 11)
      return no_match;

    if (colons > 7)
      return no_match;

    str++;
  }

  if (!prefix) {
    struct sockaddr_in6 sin6_dummy;
    int ret = inet_pton(AF_INET6, start, &sin6_dummy.sin6_addr);
    return ret == 1 ? exact_match : partly_match;
  }

  if (state < STATE_MASK)
    return partly_match;

  mask = strtol(str, &endptr, 10);
  if (*endptr != '\0')
    return no_match;

  if (mask < 0 || mask > IPV6_MAX_BITLEN)
    return no_match;

  return exact_match;
}

static enum match_type match_range(struct cmd_token *token, const char *str)
{
  assert(token->type == RANGE_TKN);

  char *endptr = NULL;
  long long val;

  val = strtoll(str, &endptr, 10);
  if (*endptr != '\0')
    return no_match;

  if (val < token->min || val > token->max)
    return no_match;
  else
    return exact_match;
}

static enum match_type match_word(struct cmd_token *token, const char *word)
{
  assert(token->type == WORD_TKN);

  // if the passed token is 0 length, partly match
  if (!strlen(word))
    return partly_match;

  // if the passed token is strictly a prefix of the full word, partly
  // match
  if (strlen(word) < strlen(token->text))
    return !strncmp(token->text, word, strlen(word)) ? partly_match
                 : no_match;

  // if they are the same length and exactly equal, exact match
  else if (strlen(word) == strlen(token->text))
    return !strncmp(token->text, word, strlen(word)) ? exact_match
                 : no_match;

  return no_match;
}

static enum match_type match_variable(struct cmd_token *token, const char *word)
{
  assert(token->type == VARIABLE_TKN);
  return exact_match;
}

#define MAC_CHARS "ABCDEFabcdef0123456789:"

static enum match_type match_mac(const char *word, bool prefix)
{
  /* 6 2-digit hex numbers separated by 5 colons */
  size_t mac_explen = 6 * 2 + 5;
  /* '/' + 2-digit integer */
  size_t mask_len = 1 + 2;
  unsigned int i;
  char *eptr;
  unsigned int maskval;

  /* length check */
  if (strlen(word) > mac_explen + (prefix ? mask_len : 0))
    return no_match;

  /* address check */
  for (i = 0; i < mac_explen; i++) {
    if (word[i] == '\0' || !strchr(MAC_CHARS, word[i]))
      break;
    if (((i + 1) % 3 == 0) != (word[i] == ':'))
      return no_match;
  }

  /* incomplete address */
  if (i < mac_explen && word[i] == '\0')
    return partly_match;
  else if (i < mac_explen)
    return no_match;

  /* mask check */
  if (prefix && word[i] == '/') {
    if (word[++i] == '\0')
      return partly_match;

    maskval = strtoul(&word[i], &eptr, 10);
    if (*eptr != '\0' || maskval > 48)
      return no_match;
  } else if (prefix && word[i] == '\0') {
    return partly_match;
  } else if (prefix) {
    return no_match;
  }

  return exact_match;
}

Coverage Report

Created: 2025-12-05 06:31