refactor wifi on linux

diff --git a/components/wifi.c b/components/wifi.c
index 313d4c6fd60efdb705122a307f53d8810a5373cf..23af2015b4046bdc019cbf71911b8add6638546c 100644 (file)
--- a/components/wifi.c
+++ b/components/wifi.c
@@ -26,24 +26,16 @@
        static char resp[4096];
 
        static char *
-       findattr(int attr, char *p, char *e, size_t *len)
+       findattr(int attr, const char *p, const char *e, size_t *len)
        {
-               struct nlattr nla;
-               size_t alen;
-
-               while ((size_t)(e-p) >= sizeof(nla)) {
+               while (p < e) {
+                       struct nlattr nla;
                        memcpy(&nla, p, sizeof(nla));
-                       if (nla.nla_len < NLA_HDRLEN)
-                               return NULL;
                        if (nla.nla_type == attr) {
-                               p += NLA_HDRLEN;
-                               *len = nla.nla_len-NLA_HDRLEN;
-                               return (size_t)(e-p)>=*len?p:NULL;
+                               *len = nla.nla_len - NLA_HDRLEN;
+                               return (char *)(p + NLA_HDRLEN);
                        }
-                       alen = NLA_ALIGN(nla.nla_len);
-                       if ((size_t)(e-p) < alen)
-                               return NULL;
-                       p += alen;
+                       p += NLA_ALIGN(nla.nla_len);
                }
                return NULL;
        }
@@ -97,9 +89,10 @@
                }
                if ((size_t)r <= sizeof(ctrl))
                        return 0;
-               p = findattr(CTRL_ATTR_FAMILY_ID, resp+sizeof(ctrl), resp+r, &len);
+               p = findattr(CTRL_ATTR_FAMILY_ID, resp + sizeof(ctrl), resp + r, &len);
                if (p && len == 2)
                        memcpy(&id, p, 2);
+
                return id;
        }
 
@@ -172,11 +165,12 @@
                        return NULL;
                }
 
-               if ((size_t)r <= NLMSG_HDRLEN+GENL_HDRLEN)
+               if ((size_t)r <= NLMSG_HDRLEN + GENL_HDRLEN)
                        return NULL;
-               p = findattr(NL80211_ATTR_SSID, resp+NLMSG_HDRLEN+GENL_HDRLEN, resp+r, &len);
+               p = findattr(NL80211_ATTR_SSID, resp + NLMSG_HDRLEN + GENL_HDRLEN, resp + r, &len);
                if (p)
                        p[len] = 0;
+
                return p;
        }
 
@@ -188,8 +182,9 @@
                uint16_t fam = nl80211fam();
                ssize_t r;
                size_t len;
-               char req[NLMSG_HDRLEN+GENL_HDRLEN+NLA_HDRLEN+NLA_ALIGN(4)] = {0}, *p = req, *e;
+               char req[NLMSG_HDRLEN + GENL_HDRLEN + NLA_HDRLEN + NLA_ALIGN(4)] = {0}, *p = req, *e;
                int idx = ifindex(interface);
+
                if (idx < 0) {
                        fprintf(stderr, "interface %s not found\n", interface);
                        return NULL;
@@ -209,16 +204,17 @@
                }, sizeof(struct genlmsghdr));
                p += GENL_HDRLEN;
                memcpy(p, &(struct nlattr){
-                       .nla_len = NLA_HDRLEN+4,
+                       .nla_len = NLA_HDRLEN + 4,
                        .nla_type = NL80211_ATTR_IFINDEX,
                }, sizeof(struct nlattr));
                p += NLA_HDRLEN;
-               memcpy(p, &(uint32_t){idx}, 4);
+               memcpy(p, &idx, 4);
 
                if (send(nlsock, req, sizeof(req), 0) != sizeof(req)) {
                        warn("send 'AF_NETLINK':");
                        return NULL;
                }
+
                *strength = 0;
                while (1) {
                        r = recv(nlsock, resp, sizeof(resp), 0);
@@ -228,9 +224,11 @@
                        }
                        if ((size_t)r < sizeof(hdr))
                                return NULL;
-                       for (p = resp; p != resp+r && (size_t)(resp+r-p) >= sizeof(hdr); p = e) {
+
+                       for (p = resp; p != resp + r && (size_t)(resp + r-p) >= sizeof(hdr); p = e) {
                                memcpy(&hdr, p, sizeof(hdr));
-                               e = resp+r-p<hdr.nlmsg_len?resp+r:p+hdr.nlmsg_len;
+                               e = resp + r - p < hdr.nlmsg_len ? resp + r : p + hdr.nlmsg_len;
+
                                if (!*strength && hdr.nlmsg_len > NLMSG_HDRLEN+GENL_HDRLEN) {
                                        p += NLMSG_HDRLEN+GENL_HDRLEN;
                                        p = findattr(NL80211_ATTR_STA_INFO, p, e, &len);
@@ -240,7 +238,7 @@
                                                snprintf(strength, sizeof(strength), "%d", RSSI_TO_PERC(*p));
                                }
                                if (hdr.nlmsg_type == NLMSG_DONE)
-                                       return *strength?strength:NULL;
+                                       return *strength ? strength : NULL;
                        }
                }
        }