Is it a rock song?
This is a Hip-Hop / Rap Song and not Rock.
As to why it can't be called Rock, it would need one to spell out the specific differences between the two styles. Though, in general, an educated guess can usually be made by the following few factors:
- A rock song would quite prominently contain the extended plays of Electric Guitar rhythms and melodies, whereas a Hip-Hop track generally tends to be heavy on claps and drums.
If you're reading out the lyrics of a rock song (let's say, without hearing it before), you'll find that the rhyme in the lyrics comes by pretty naturally and consistently, generally occurring in the same pattern. So it would appear more like a poetry in that sense.
Reading the lyrics of a rap / hip-hop song, you'll notice that is often unlikely to produce rhymes in a consistent pattern (if at all there's any), making them appear like a loosely constructed poetry and more like a prose. This brings us to...
Vocalists in a rock song would actually sing, which means differences between the pitch and volume would be noticeable depending on the emotions expressed through the lyrics. Sounds and syllables are usually extended to enhance the effect of a performance.
A rap song is generally not concerned with the singing capabilities of the performer in a classical sense. Naturally, there's comparatively less variations between the pitch and volume in a rap song. The complexity (and the skill thus required) then increases by the fact that, the sounds and syllables of several words are often cleverly ommitted, gobbled up and intentionally pronounced differently to create an impression of "rhyming". It may be worthwhile to mention that, rhyming in rap songs isn't just limited to the end of the line word / syllable, but they even make attempts to create as many (apparently) "rhyming" words within a single line too - see Internal Rhyme.
You'll probably also notice that there are several tracks where there's a sort of overlap between Rock and Hip-Hop / Rap. Two well known tracks:
- Eminem - Sing For the Moment: This is a rap, but also contains a sample from a rock song: Aerosmith - Dream On
- Linkin' Park - In the End: Pretty much a Hard Rock song so to speak, but is enriched with some immense rapping by Mike Shinoda.
The purpose of serving these two examples is to demonstrate that even though some portions of a song of one style might seem to corroborate more with the other style, it is the dominant style that the song gets identified by.