net: support carrier detection and total data transfer rate

- for each interface, read carrier info from sysfs into
  args["{"..name.." carrier}"], 1 means 'link up', 0 'link down'
- the carrier info for the 'total' pseudo-interface is a logical or of
  the carriers of the summed interfaces (i.e. those not contained in
  the ignore list)
- sum rates of all interfaces (except the ones in an ignore list) and
  make them available under the interfacename "total"

Signed-off-by: Adrian C. (anrxc) <anrxc@sysphere.org>

extra/net.lua

@@ -0,0 +1,138 @@
+---------------------------------------------------
+-- Licensed under the GNU General Public License v2
+--  * (c) 2010, Adrian C. <anrxc@sysphere.org>
+--  * (c) 2009, Henning Glawe <glaweh@debian.org>
+--  * (c) 2009, Lucas de Vries <lucas@glacicle.com>
+---------------------------------------------------
+
+-- {{{ Grab environment
+local pairs = pairs
+local tonumber = tonumber
+local os = { time = os.time }
+local io = { lines = io.lines }
+local setmetatable = setmetatable
+local string = { match = string.match }
+local helpers = require("vicious.helpers")
+-- }}}
+
+
+-- Net: provides usage statistics for all network interfaces
+module("vicious.widgets.net")
+
+
+-- Initialise function tables
+local nets = {}
+-- Variable definitions
+local unit = { ["b"] = 1, ["kb"] = 1024,
+    ["mb"] = 1024^2, ["gb"] = 1024^3
+}
+
+-- {{{ Net widget type
+local function worker(format, tignorelist)
+    local args    = {}
+    local tignore = {}
+    local total_rx = 0
+    local total_tx = 0
+    local any_up   = 0
+
+    if not tignorelist then
+        tignorelist = {"lo", "wmaster0"}
+    end
+    for k, i in pairs(tignorelist) do
+        tignore[i] = true
+    end
+
+    -- Get NET stats
+    for line in io.lines("/proc/net/dev") do
+        -- Match wmaster0 as well as rt0 (multiple leading spaces)
+        local name = string.match(line, "^[%s]?[%s]?[%s]?[%s]?([%w]+):")
+        if name ~= nil then
+            -- Received bytes, first value after the name
+            local recv = tonumber(string.match(line, ":[%s]*([%d]+)"))
+            -- Transmited bytes, 7 fields from end of the line
+            local send = tonumber(string.match(line,
+             "([%d]+)%s+%d+%s+%d+%s+%d+%s+%d+%s+%d+%s+%d+%s+%d$"))
+
+            if not tignore[name] then
+                total_rx = total_rx + recv
+                total_tx = total_tx + send
+            end
+
+            helpers.uformat(args, name .. " rx", recv, unit)
+            helpers.uformat(args, name .. " tx", send, unit)
+
+            if nets[name] == nil then
+                -- Default values on the first run
+                nets[name] = {}
+
+                helpers.uformat(args, name .. " down", 0, unit)
+                helpers.uformat(args, name .. " up",   0, unit)
+                args["{"..name.." carrier}"] = 0
+
+                nets[name].time = os.time()
+            else -- Net stats are absolute, substract our last reading
+                local interval  = os.time() - nets[name].time >  0 and
+                                  os.time() - nets[name].time or 1
+                nets[name].time = os.time()
+
+                local down = (recv - nets[name][1]) / interval
+                local up   = (send - nets[name][2]) / interval
+
+                helpers.uformat(args, name .. " down", down, unit)
+                helpers.uformat(args, name .. " up",   up,   unit)
+
+                -- Carrier detection
+                sysnet = helpers.pathtotable("/sys/class/net/" .. name)
+
+                if sysnet.carrier then
+                    ccarrier = tonumber(sysnet.carrier)
+
+                    args["{"..name.." carrier}"] = ccarrier
+                    if ccarrier ~= 0 and not tignore[name] then
+                        any_up = 1
+                    end
+                else
+                    args["{"..name.." carrier}"] = 0
+                end
+            end
+
+            -- Store totals
+            nets[name][1] = recv
+            nets[name][2] = send
+        end
+    end
+
+    helpers.uformat(args, "total rx", total_rx, unit)
+    helpers.uformat(args, "total tx", total_tx, unit)
+
+    if nets["total"] == nil then
+        -- Default values on the first run
+        nets["total"] = {}
+
+        helpers.uformat(args, "total down", 0, unit)
+        helpers.uformat(args, "total up",   0, unit)
+        args["{total carrier}"] =   0
+
+        nets["total"].time = os.time()
+    else -- Net stats are absolute, substract our last reading
+        local interval = os.time() - nets["total"].time >  0 and
+                         os.time() - nets["total"].time or 1
+        nets["total"].time = os.time()
+
+        local down = (total_rx - nets["total"][1]) / interval
+        local up   = (total_tx - nets["total"][2]) / interval
+
+        helpers.uformat(args, "total down", down, unit)
+        helpers.uformat(args, "total up",   up,   unit)
+        args["{total carrier}"] = any_up
+    end
+
+    -- Store totals
+    nets["total"][1] = total_rx
+    nets["total"][2] = total_tx
+
+    return args
+end
+-- }}}
+
+setmetatable(_M, { __call = function(_, ...) return worker(...) end })