Small fix for parse_ipv4

Still problems on 32bit due to issues discussed in JuliaLang#3447

base/socket.jl

@@ -144,8 +144,14 @@ function parse_ipv4(str)
  end
  if f[1] == '0'
  if length(f) >= 2 && f[2] == 'x'
+ if length(f) > 8 # 2+(3*2) - prevent parseint from overflowing on 32bit
+ error("IPv4 field too large")
+ end
  r = parseint(f[3:end],16)
  else 
+ if length(f) > 9 # 1+8 - prevent parseint from overflowing on 32bit
+ error("IPv4 field too large")
+ end
  r = parseint(f,8)
  end
  else
@@ -157,7 +163,7 @@ function parse_ipv4(str)
  end
  ret |= uint32(r) << ((4-i)*8)
  else
- if r > ((uint64(1)<<((5-length(f))*8))-1)
+ if r > ((uint64(1)<<((5-length(fields))*8))-1)
  error("IPv4 field too large")
  end
  ret |= r